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Cloves are the aromatic flower buds of a tree in the Myrtaceae family

Clove

Syzygium aromaticum Myrtaceae

Clove has been used for thousands of years as both food and medicine. Its unique phytochemistry has been the focus of some interesting research which offers deeper insights into its traditional uses, as well as new ideas for the modern potential of this herb.

Sustainability status

Not currently on risk lists but complete data may be missing on the status of the species. Commonly cultivated though may be sourced from the wild. Only source cultivated supplies or from certified sustainable wild collection. Read more about our sustainability guide.

Sustainability Status
Key benefits
  • Local anodyne
  • Dental pain
  • Low mood
  • Respiratory congestion
  • Poor digestion
  • Erectile dysfunction
  • Aphrodisiac
  • How does it feel?

    Cloves have a completely unique flavour profile. They are highly aromatic and pungent, with sweet, warming, and slightly peppery tones. If you chew on a whole clove or put a little powdered clove in the mouth, it will leave a lingering, numbing sensation in the mouth.

  • What can I use it for?

    Clove tree (Syzygium aromaticum)
    Clove tree (Syzygium aromaticum)

    Clove has a strong reputation as a local anodyne (pain reliever) for dental pain (9). It is often used in powdered form or as a diluted pure essential oil (see dosage for instructions) applied directly onto the affected gum. Essential oils are powerful substances and must be used with caution, so follow our advice for the correct application of clove for dental pain.

    As a common kitchen ingredient, clove is often close at hand and makes an excellent digestive remedy, particularly where there is sluggishness or a low state of function in the upper and lower digestive tract. It can help speed up digestive processes and calm spasms in the intestines (9).

    Clove can also help to relieve flatulence, an action known as carminative (9). It soothes stomach cramps due to these digestive actions and its analgesic effects. It has a post-digestive effect (9) which means it can help support digestive processes lower down in the digestive tract.

    Cloves also have expectorant properties which may help reduce the severity of coughs by improving the clearance of phlegm in the lungs (9). This may be used for spasmodic coughs as well as for laryngitis, bronchitis or sore throats (9).

    The essential oil of clove diluted into a carrier oil can be used topically for muscular pain and cramping, as well as for the relief of headaches and lower back pain (9). The essential oil of clove also has mood-enhancing effects and can be used as an aphrodisiac (12).

  • Into the heart of Clove

    Clove flower buds (Syzygium aromaticum)
    Clove flower buds (Syzygium aromaticum)

    Energetically, clove is sweet, pungent and warming due to its unique combination of phytochemicals and aromatic compounds. The essential oil of clove is popular in aromatherapy where it is used for severe fatigue, low energy and depression (12).

    In traditional Chinese medicine (TCM) cloves help qi (life force) to descend (11), which is related to the Western carminative action. This action makes it an excellent herb to use for the relief of nausea and vomiting, as well as for excessive flatulence and hiccoughs (11). For this application, cloves combine well with ginger and cardamom drunk as an infusion (tea) (9).

    This grounding downward energy of clove is especially helpful where nausea is connected to anxious or nervous feelings.  (11).

    In Ayurvedic medicine, there is a different model and understanding of holistic physiology that is used as a way to understand patterns of imbalance. Ayurveda also has its own unique philosophy and understanding of herbal qualities that, built up over thousands of years.

    There are three doshas: vata, pitta and kapha. Their energies are believed to circulate in the body and govern physical, mental and emotional characteristics. They are described as follows; Vata controls basic bodily functions as well as the mind. Pitta governs metabolism, digestion and hormones linked to appetite. Kapha is responsible for strength and stability, muscle growth, weight and the immune system. 

    Clove is described in Ayurveda as having a KPV- (kapha, pitta, vata) effect (9). This means that its predominant action is in reducing excess kapha activity in the body. Excess in kapha may manifest as stagnation or congestion in the tissues. This may be demonstrated by some of clove’s best-known uses. Kapha may manifest as lethargy and low mood, and clove is understood to clear the orifices of the head, making way for higher clarity (9). Kapha may also manifest as congestion in the lungs; clove helps to clear this type of congestion or stagnation (9).

  • Traditional uses

    Young clove flower buds (Syzygium aromaticum)
    Young clove flower buds (Syzygium aromaticum)

    The earliest written evidence of cloves being used as food or medicine dates back to around the year 300 B.C. During the Han Dynasty of China, clove was referenced for use as a breath freshener (7).

    Until the last few hundred years, cloves were exclusively grown in the famous ‘spice islands’ off the coast of North Indonesia during the years of Dutch colonisation. At its peak, the value of cloves rivalled that of oil (7). Other sources suggest that ‘cloves and nutmeg were among the most precious items of Europe of the 16th and 17th centuries, and they were worth more than their weight in gold’ (10).

    In the 18th century, clove plants were smuggled out of the spice islands and eventually found their way to Zanzibar, which is the most prolific producer of cloves today (7).

    Traditionally, cloves and their oil were used to relieve nausea and vomiting, flatulence, and to strengthen digestion (10). In a UCLA (University of California) biomedical library’s history and special collections article, it is said that ‘the oil of cloves sometimes afforded relief when introduced into the cavity of a carious tooth (10)’.

  • Traditional actions

  • What practitioners say

    Young clove tree (Syzygium aromaticum)
    Young clove tree (Syzygium aromaticum)

    Digestive system

    Clove has many beneficial effects in the digestive system. It helps to relieve intestinal spasm and can also improve the appetite. Due to its anti-fungal effects clove may be used as part of a treatment approach to tackle Candida albicans (9). It has a wide range of antibacterial and anti-fungal actions (9) which may make it a useful herb for associated dysbiotic conditions in the gastrointestinal tract.

    Herbalists may use clove among other herbs such as neem, calendula or triphala to address candida and intestinal dysbiosis. Lifestyle and dietary interventions are vital elements of treatment for correcting such imbalances. Reducing sugar during the treatment of fungal infections or dysbiosis is essential, as fungus and bacteria thrive on sugars.

    Clove has also long been used for the treatment of intestinal parasites such as worms. This is thought to be due to the damaging impact of clove’s constituents on the cuticle and tegument of helminths (13). As with the above, there are a number of important elements to the effective elimination of parasites which may also include dietary and lifestyle changes.

    Respiratory system

    Cloves are used for conditions associated with congestion and stuck phlegm in the lungs due to their expectorant properties. They may be useful as part of an approach to treat bronchitis, coughs, asthma and pleurisy. 

    Cloves have an anti-spasmodic action on the lung tissue which may also contribute to its benefit for use in asthma (9). To effectively support patients with asthma, a herbalist may use expectorant and anti-spasmodic herbs like clove along with other herbs like black seed to support lung health. 

    Reproductive system

    Clove may sometimes be used for conditions that affect sexual function in both men and women. It has a strong history of use for male reproductive conditions as well as some promising modern research. This includes the treatment of premature ejaculation and impotence. The mechanism of action for this is unclear. However, clinical trials have demonstrated the efficacy of clove for male reproductive conditions (2) which may support an indication for this application in practice.

    Clove also has mood-enhancing and aphrodisiac qualities which means it may also be able to help improve sex drive for those who suffer from low libido (9).

  • Research

    Farmer spreading cloves to dry on a thatched mat at Pemba Island, Zanzibar, Tanzania
    Farmer spreading cloves to dry on a thatched mat at Pemba Island, Zanzibar, Tanzania

    There are a good number of studies, including some interesting clinical trials, on clove and some of its bioactive compounds. Among the studies and reviews included, there may be reference to animal studies that demonstrate the mechanism of action for some clove’s medicinal properties. Animal studies are not condoned by herbal reality, however, for the purpose of including research from which some understanding of therapeutic actions can be confirmed, some animal studies have been included.

    A randomised double-blind clinical trial of polyphenolic clove extracts in the treatment of metabolic syndrome

    A randomised double-blinded comparative study was carried out to investigate the effects of a clove bud polyphenol extract called Clovinol on metabolic syndrome in 70 healthy adults. The study compared the effects of Clovinol with synthetic glutathione (s-GSH) given at 250 mg a day over a period of 84 days. 

    Treatment with Clovinol significantly increased the total leukocyte (white blood cell) and reduced neutrophil/lymphocyte ratio and inflammatory markers, all of which are vital in mounting healthy immune responses. It also improved markers for plasma concentration of endogenous antioxidants, inflammatory markers, blood sugar, lipid metabolism and insulin resistance markers. It also significantly reduced total cholesterol, triglycerides, low-density lipoproteins and increased high-density lipoproteins (1). The synthetic GSH showed no significant effect on blood glucose and lipid metabolism (1).

    A randomised double-blind placebo-controlled trial on topical clove gel for premature ejaculation

    A double-blind randomised placebo-controlled study was carried out to identify the potential of a topical extract of clove oil for the treatment of premature ejaculation. The study was carried out for a period of 8 weeks where 22 subjects who had been randomly assigned into two groups to receive either clove 1% gel or placebo gel 10 minutes before intercourse.

    The study results showed a significant improvement in intercourse satisfaction ratings as well as a significant improvement in erectile performance, and erectile function including prolonged ejaculatory latency timescale in the clove gel group. No adverse effects were observed (2). 

    Inhibition of dengue virus by compounds isolated from clove flower buds

    DENV protease is considered an important target for identifying new protocols for the treatment of the dengue virus because of its crucial role in the viral replication cycle. This report discusses DENV protease inhibitor eugeniin, an important compound isolated from cloves, along with two other milder inhibitors, isobiflorin and biflorin. The mechanisms by which these compounds may actively inhibit dengue virus are summarised in the context of antiviral therapeutics. The review concludes that the findings show promising development, considering there is currently still no specific antiviral treatment available against dengue fever (3).

    Cloves (Syzygium aromaticum)
    Cloves (Syzygium aromaticum)

    Comparative Anticancer Potential of Clove Against Cancer Cell Lines of Various Anatomical Origin

     Clove was investigated in vitro to determine whether three different extracts had any activity against cancer cells (4). Water, ethanol and oil extracts were screened for anti-proliferative activity against HeLa (cervical cancer), MCF-7 (ER + ve) and MDA-MB-231 (ER – ve) breast cancer, DU-145 prostate cancer and TE-13 esophageal cancer cell lines, along with normal human peripheral blood lymphocytes. In the examined five cancer cell lines, the extracts showed different patterns of cell growth inhibition activity, with the oil extract having maximal cytotoxic activity. Morphological analysis and DAPI staining showed cytotoxicity as a result of cell disruption with subsequent membrane rupture. The oesophageal cancer cell lines were most sensitive to the clove extract (4). This study was only done on cells, so cloves may not have the same effect on people, but this research does show the need for further clinical trials. 

    A randomised triple-blind trial on clove mouthwash for the incidence of ventilator-associated pneumonia in intensive care unit patients

    A comparative, randomised, triple-blind, clinical trial was carried out to identify the effects of clove on ventilator-associated pneumonia in intensive care unit patients. 168 hospital patients were divided into intervention and control groups to either receive a clove extract mouthwash at 6.66% concentration or chlorhexidine 0.2% twice a day for a period of 5 days. The study showed that the risk of illness was 2.06 times higher in the control group than in the clove extract group, and so the clove mouthwash significantly reduced the risk of ventilator-associated pneumonia (5). 

    Evaluation of Clove Phytochemicals as Potential Antiviral Drug Candidates Targeting SARS-CoV-2 Main Protease: Computational Docking, Molecular Dynamics Simulation, and Pharmacokinetic Profiling

    An evaluation of natural phytochemicals isolated from clove was carried out to ascertain their effects against the main protease (an enzyme that breaks down the proteins or peptides responsible for the viral replication inside the host) of SARS-CoV-2. This paper discussed the mechanism by which viral replication inhibition is possible by targeting the SARS- CoV-2 protease.

    Some of the most relevant constituents discussed in this paper were syzyginin B, eugenol, and casuarictin. These all demonstrated potential binding properties against the target SARS-CoV-2 main protease. Whilst these results show some direct beneficial potential of clove phytochemicals, these tests were by analysis and lab studies. Human studies are required to fully establish the prospects of clove as an anti-viral medicine (6).

  • Did you know?

    Spices such as clove, nutmeg and mace were exclusively found growing on the islands that were known as the Spice Islands in the Northeast of Indonesia. The presence of these precious spices sparked colonial interest in Europe in the 16th century. 

    During the years of Dutch colonisation, it is said that the wild clove trees were destroyed from the surrounding native islands to secure a monopoly; the spice islands were colonised and the plantations of clove and nutmeg among other spices were managed under strict export. In the 18th century, cloves were smuggled out of the spice islands and introduced to Mauritius where they began to be cultivated, eventually finding their way to Penang, Sumatra and Zanzibar, which is the most prolific producer of cloves today (7).

    Croucher (8) states in an article written on clove plantations in relation to African archaeology that ‘clove plantations on nineteenth-century Zanzibar were sites on which many recent immigrants from Oman and Africa constructed new identities within the complex social relations of colonial rule, enslavement and concubinage (8)’.

    Croucher then continues, that ‘clove plantations allow for reflections back on the broader field of historical archaeology. In turn, this may allow for a clearer understanding of the particularities of colonialism and capitalism in many different places (8)’.

Additional information

  • Botanical description

    Clove is a slow growing evergreen tree that grows to a wide range of different heights between 8 metres to 20 metres. It flowers after about 6 years and takes up to 20 years to reach maturity and can bear fruit for more than 80 years. Each leaf is around 10cm long and 5cm wide, elliptic or oblong, very narrowly attenuated at the base, and points upwards. The undersides of the leaves have black spots. New leaves are bright pink in colour and turn light green and glossy. They are simple with leathery and shiny texture on the upper (adaxial) surface. They are arranged opposite each other, and are aromatic when crushed.

    Each flower is about 6mm wide and occurs in terminal clusters. The unopened flower buds are green at first, slowly changing to pink, red or crimson, then finally bright red when in full bloom.

    Fruits are dark purple, oblong, about 2-2.5cm long and 1.3cm wide containing a single seed.

  • Common names

    • Cloves
    • Clove Tree
    • Tropical Myrtle
    • Zanzibar Redhead
  • Safety

    Cloves in culinary doses are not known to be toxic.

    Pure eugenol, a compound contained in cloves, is toxic in relatively small quantities. For example, a dose of 5–10 ml has been reported as being a near-fatal dose for a two-year-old child (7). These dosages of eugenol may be possible if using an essential oil internally. Essential oils must therefore be avoided in children or minors.

  • Interactions

    No herb-drug interactions are known (9).

  • Contraindications

    Clove is contraindicated for high pitta people/conditions according to Ayurvedic practice(9).

  • Preparation

    • Tincture
    • Tea
    • Powdered herb
  • Dosage

    Tincture (1:5 in 70%): Take between 2 – 3ml in a little water up to 3 times a day.

    Decoction: To make a decoction place 1-3g of dried material in one cup of boiling water, simmer gently for between 15 – 20 minutes. This should be drunk hot twice a day.

    Dental pain: For best results in treating dental pain, use ground or powdered clove. Take a small pinch and rub directly into the gum/ affected area (not the tooth itself).

    Essential oils used internally are rarely recommended due to their powerful nature. Diluted clove essential oil is sometimes used for dental pain. To use clove oil for a toothache; Add 3 -5 drops of pure organic clove essential oil to 1 teaspoon of an edible neutral carrier oil like olive oil, canola oil, grapeseed oil, or sweet almond oil. Using a ball of cotton wool or Q-tip, apply the diluted clove oil to the affected gum (not the tooth).

  • Plant parts used

    The flower buds

  • Constituents

    Volatile oils: Eugenol makes up between 72–90% of the clove volatile oil fraction. It is also the compound most responsible for its aromatic quality. Other aromatic compounds include acetyl eugenol, beta-caryophyllene and vanillin and crategolic acid.

    Tannins: Bicornin, gallotannicacid, methyl salicylate (anodyne effects)

    Flavonoids: Eugenin, kaempferol, rhamnetin

    Triterpenoids: Oleanolic acid, stigmasterol and campesterol (1)

Clove illustration (Syzygium aromaticum)
  • Habitat

    Clove is native to the North Moluccas Islands in Indonesia. Other significant plantations are in Sri Lanka.

  • Sustainability

    The IUCN Red List of Threatened Plants database does not yet include clove. It is uncertain whether clove is still found growing wild in its natural native habitat.

    Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must therefore ensure that we source our medicines with sustainability in mind. 

    The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

    The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world are now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

    Read our article on Herbal quality & safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

  • Quality control

    Clove flower buds are collected when the lower flower parts turn green-crimson. Commercially grown cloves are dried in the open air and separated from their pedicel (or stems-,which are also sold commercially). If the buds are left too long on the tree they will open and continue to mature. The petals fall leaving ‘brown cloves’ on the tree from which the fruits, called ‘mother cloves’, are produced.

    Dried clove buds are harvested when the buds have reached their full size, but before they fully open or mature, and the hypanthium (cup like part of the flower from which the ovary forms) has turned reddish.

    Harvesting clove buds should be undertaken at the right stage. Early picking, fallen and over-ripe buds will produce buds of lower quality (7).

    Herbal Medicines are often extremely safe to take, however it is important to buy herbal medicines from a reputed supplier. Sometimes herbs bought from unreputable sources are contaminated, adulterated or substituted with incorrect plant matter.

    Some important markers for quality to look for would be to look for certified organic labelling, ensuring that the correct scientific/botanical name is used and that suppliers can provide information about the source of ingredients used in the product.

    A supplier should be able to tell you where the herbs have come from. There is more space for contamination and adulteration when the supply chain is unknown.

  • How to grow

    Close up of Cloves (Syzygium aromaticum)
    Close up of Cloves (Syzygium aromaticum)

    Due to their tropical origin and specific location requirements, it can be difficult to grow clove trees in colder climates, such as in the United Kingdom. Their native climes offer warm temperatures year-round, as well as consistent humidity.

    • Clove seeds can be propagated in the middle of the summer. Another difficult element to growing cloves is that seeds should be planted immediately after harvesting. It is possible to buy saplings of clove.
    • Unless these environmental needs can be met, one may attempt to grow clove trees in tubs in a heated greenhouse or a warm sunny and spacious living room. They can be put outdoors during the warm summer months but in a protected location. They may remain outdoors from May or June until the end of August or early September, depending on the temperature and sunlight available to them. 
    • Clove trees do not tolerate significant temperature fluctuations. Their natural growing environment is that of the oceanic climate of Southeast Asia. Throughout the growing season, ensure that temperatures remain as consistent as possible.
    • Cloves prefer full sun but can be grown in partial shade. They require deep, fertile and well-drained soil. 
    • They require plenty of water – the soil should remain consistently moist. Water-logging is however not advised as this may hinder their flowering abilities.
  • Recipe

    Clove tea (Syzygium aromaticum)
    Clove tea (Syzygium aromaticum)

    Pain-relieving massage oil

    A massage oil for arthritis, sciatica and joint pain can be made using arnica-infused oil, clove essential oil and ginger essential oil.

    Blend 5 drops of clove and 5 drops of ginger essential oils into 50ml of arnica-infused oil and apply to affected areas two or three times a day.

    Chai tea

    Cloves are one of the main ingredients for chai tea, a classic blend of Indian and Asian herbs that includes ginger, cardamom, nutmeg, cinnamon, cloves, black pepper, hot water and hot milk. Black tea leaves may also be added. Chai is a favourite daily brew that offers a wide range of health benefits.

    • The best way to brew chai is to use whole, dried spices and crush or grind them a little to release their full aroma. 
    • Once the spices have been crushed a little, they can be placed into a pan with a cup of half water / half milk (you can use all milk for a creamier taste). Gently bring to a boil and then reduce the heat to a simmer, keeping the lid on (to preserve all the medicinal volatile oils) for between 15 – 20 minutes.
    • Remove from the heat. If using black tea leaves, you can add a tea bag to the pan and brew for a further 1 – 2 minutes off the heat. Otherwise, strain the spices out of the milk and pour into a cup.
    • You can use honey, sugar or an alternative sweetener to taste. Drink freely throughout the day.
  • References

    1. Thomas, J., Patel, A., Das Sivadasan, S., Sreevallabhan, S., Illathu Madhavamenon, K., & Mohanan, R. (2022). Clove bud (Syzygium aromaticum L.) polyphenol helps to mitigate metabolic syndrome by establishing intracellular redox homeostasis and glucose metabolism: A randomized, double-blinded, active-controlled comparative study. Journal of Functional Foods, 98, 105273. https://doi.org/10.1016/j.jff.2022.105273
    2. Sharifi Olounabadi, A. R., Khayyamfar, F., Kamalinejad, M., Salesi, M., Alijaniha, F., Emadi, F., Ghaffari, F., Daneshfard, B., & Naseri, M. (2021). Effect of Topical Clove (Syzygium aromaticum (L.) Merr. & L.M.Perry) Gel on Premature Ejaculation: A Pilot Randomized Double-Blind Placebo-Controlled Clinical Trial. Traditional and Integrative Medicine. https://doi.org/10.18502/tim.v6i3.7312
    3. Saleem, H. N., Batool, F., Mansoor, H. J., Shahzad-ul-Hussan, S., & Saeed, M. (2019). Inhibition of Dengue Virus Protease by Eugeniin, Isobiflorin, and Biflorin Isolated from the Flower Buds of Syzygium aromaticum (Cloves). ACS Omega, 4(1), 1525–1533. https://doi.org/10.1021/acsomega.8b02861
    4. Comparative Anticancer Potential of Clove (Syzygium aromaticum) – an Indian Spice – Against Cancer Cell Lines of Various Anatomical Origin. (2011). Asian Pacific Journal of Cancer Prevention, 12(8), 1989–1993. https://journal.waocp.org/article_25825.html
    5. Mojgan Jahanshir, Monir Nobahar, Ghorbani, R., & Malek, F. (2023). Effect of clove mouthwash on the incidence of ventilator-associated pneumonia in intensive care unit patients: a comparative randomized triple-blind clinical trial. https://doi.org/10.1007/s00784-023-04972-w
    6. Manivannan, A. C., Malaisamy, A., Eswaran, M., Meyyazhagan, A., Arumugam, V. A., Rengasamy, K. R., Balasubramanian, B., & Li, W. (2022). Evaluation of clove phytochemicals as potential antiviral drug candidates targeting SARS-COV-2 main protease: computational docking, molecular dynamics simulation, and pharmacokinetic profiling. Frontiers in Molecular Biosciences, 9. https://doi.org/10.3389/fmolb.2022.918101
    7. MONOGRAPH OF CLOVE. (n.d.). Retrieved November 1, 2023, from https://svbpharmacy.org/wp-content/uploads/2021/05/monograph-clove.pdf
    8. Croucher, S. K. (2007). Clove plantations on nineteenth-century Zanzibar. Journal of Social Archaeology, 7(3), 302–324. https://doi.org/10.1177/1469605307081390
    9. Pole, S. (2013). Ayurvedic medicine : the principles of traditional practice. Singing Dragon, Cop.
    10. Medicinal Spices Exhibit – UCLA Biomedical Library: History & Special Collections. (n.d.). Unitproj.library.ucla.edu. Retrieved November 2, 2023, from https://unitproj.library.ucla.edu/biomed/spice/index.cfm?displayID=7#:~:text=Cloves%20and%20nutmeg%20were%20among
    11. Clove, a Spice That’s Extra Nice. (2020, December 7). Solidago School of Herbalism. https://www.solidagoherbschool.com/blog/2020/12/4/pzlyjvnquk2dpmjstxeg5mr7g98mr8#:~:text=Energetics%20and%20Taste
    12. Kenner, D., & Yves Requena. (2001). Botanical medicine : a European professional perspective. Paradigm Publications.
    13. Ježek, J., Mirtič, K., Rešetič, N., Hodnik, J. J., & Vergles Rataj, A. (n.d.). The effect of pumpkin seed cake and ground cloves (Syzygium aromaticum) supplementation on gastrointestinal nematode egg shedding in sheep. Parasite, 28, 78. https://doi.org/10.1051/parasite/2021076
Aromatic
An ‘aromatic’ remedy, high in volatile essential oils, was most often associated with calming and sometimes ‘warming’ the digestion. Most kitchen spices and herbs have this quality: they were used both as flavouring and to ease the digestion of sometimes challenging pre-industrial foods. Many aromatics are classed as ‘carminatives’ and are used to reduce colic, bloating and agitated digestion. They also often feature in respiratory remedies for colds, chest and other airway infections. They are also classic calming inhalants and massage oils, and are the basis of aromatherapy for their mental benefits.
Astringent taste
The puckering taste you get with many plants (the most familiar is black tea after being stewed too long, or some red wines) is produced by complex polyphenols such as tannins. Tannins are used in concentrated form (eg from oak bark) to make leather from animal skins. The process of ‘tanning’ involves the coagulation of relatively fluid proteins in living tissues into tight clotted fibres (similar to the process of boiling an egg). Tannins in effect turn exposed surfaces on the body into leather. In the case of the lining of mouth and upper digestive tract this is only temporary as new mucosa are replenished, but in the meantime can calm inflamed or irritated surfaces. In the case of open wounds tannins can be a life-saver – when strong (as in the bark of broadleaved trees) they can seal a damaged surface. One group of tannins, the reddish-brown ‘condensed tannins’ are procyanidins, which can reduce inflammation and oxidative damage.
Bitter
Bitters are a very complex group of phytochemicals that stimulate the bitter receptors in the mouth. They were some of the most valuable remedies in ancient medicine. They were experienced as stimulating appetite and switching on a wide range of key digestive functions, including increasing bile clearance from the liver (as bile is a key factor in bowel health this can be translated into improving bowel functions and the microbiome). Many of these reputations are being supported by new research on the role of bitter receptors in the mouth and elsewhere round the body. Bitters were also seen as ‘cooling’ reducing the intensity of some fevers and inflammatory diseases.
Blue-purple colouring
Any fruits with a blue-purple colouring contain high levels of the polyphenols known as anthocyanins. These work 1) on the walls of small blood vessels, helping to maintain capillary structure to reduce a key stage in inflammation, and improving the microcirculation to the tissues; 2) to improve retinal function and vision; 3) to support connective tissue repair around the body.
Cooling
Traditional ‘cold’ or cooling’ remedies often contain bitter phytonutrients such a iridoids (gentian), sesiquterpenes (chamomile), anthraquinones (rhubarb root), mucilages (marshmallow), some alkaloids and flavonoids. They tend to influence the digestive system, liver and kidneys. Cooling herbs do just that; they diffuse, drain and clear heat from areas of inflammation, redness and irritation. Sweet, bitter and astringent herbs tend to be cooling.
Hot
Traditional ‘hot’ or ‘heating’ remedies, often containing spice ingredients like capsaicin, the gingerols (ginger), piperine (black or long pepper), curcumin (turmeric) or the sulfurous isothiocyanates from mustard, horseradich or wasabi, generate warmth when taken. In modern times this might translate as thermogenic and circulatory stimulant effects. There is evidence of improved tissue blood flow with such remedies: this would lead to a reduction in build-up of metabolites and tissue damage. Heating remedies were used to counter the impact of cold, reducing any symptoms made worse in the cold. .
Mucilaginous
Mucilages are complex carbohydrate based plant constituents with a slimy or ‘unctuous’ feel especially when chewed or macerated in water. Their effect is due simply to their physical coating exposed surfaces. From prehistory they were most often used as wound remedies for their soothing and healing effects on damaged tissues. Nowadays they are used more for these effects on the digestive lining, from the throat to the stomach, where they can relieve irritation and inflammation such as pharyngitis and gastritis. Some of the prominent mucilaginous remedies like slippery elm, aloe vera and the seaweeds can be used as physical buffers to reduce the harm and pain caused by reflux of excess stomach acid. Mucilages are also widely used to reduce dry coughing. Here the effect seems to be by reflex through embryonic nerve connections: reduced signals from the upper digestive wall appear to translate as reduced activity of airway muscles and increased activity of airway mucus cells. Some seed mucilages, such as in psyllium seed, flaxseed (linseed) or guar bean survive digestion to provide bulking laxative effects in the bowel. These can also reduce rate of absorption of sugar and cholesterol. .
New-mown hay aroma
The familiar country odour of haymaking, of drying grass and other plants, is largely produced by coumarins (originally isolated from tonka beans – in French coumarou) and widely used in perfumery. They are chemically categorised as benzopyrone lactones and are important phytochemicals, with strong antioxidant activity in the laboratory and likely effects in modulating inflammation. They were most often associated with the calming effect linked to their use in stuffing mattresses and pillows and plants, high In coumarins were commonly used for these properties.
Resinous
Resins are most familiar as tacky discharges from pine trees (and as the substance in amber, and rosin for violin bows). They were most valued however as the basis of ancient commodities like frankincense and myrrh (two of the three gifts of the Three Wise Men to the baby Jesus) and getting access to their source was one benefit to Solomon for marrying the Queen of Sheba (now Ethiopia). Resins were the original antiseptic remedies, ground and applied as powders or pastes to wounds or inflamed tissues, and were also used for mummification. With alcohol distillation it was found that they could be dissolved in 90% alcohol and in this form they remain a most powerful mouthwash and gargle, for infected sore throats and gum disease. They never attracted much early research interest because they permanently coat expensive glassware! For use in the mouth, gums and throat hey are best combined with concentrated licorice extracts to keep the resins in suspension and add extra soothing properties. It appears that they work both as local antiseptics and by stimulating white blood cell activity under the mucosal surface. They feel extremely effective!
Salty
The salty flavour is immediately distinctive. A grain dropped onto the tongue is instantly moistening and a sprinkle on food enkindles digestion. This easily recognisable flavour has its receptors right at the front of the tongue. The salty flavor creates moisture and heat, a sinking and heavy effect which is very grounding for the nervous system and encourages stability. People who are solid and reliable become known as ‘the salt of the earth'.
Sharpness
The sharp taste of some fruits, and almost all unripe fruits, as well as vinegar and fermented foods, is produced by weak acids (the taste is generated by H+ ions from acids stimulating the sour taste buds). Sour taste buds are hard-wired to generate immediate reflex responses elsewhere in the body. Anyone who likes the refreshing taste of lemon or other citrus in the morning will know that one reflex effect is increased saliva production. Other effects are subjective rather than confirmed by research but there is a consistent view that they include increased digestive activity and contraction of the gallbladder.
Sweet
In the days when most people never tasted sugar, ‘sweetness’ was associated with the taste of basic foods: that of cooked vegetables, cereals and meat. In other words sweet was the quality of nourishment, and ‘tonic’ remedies. Describing a remedy as sweet generally led to that remedy being used in convalescence or recovery from illness. Interestingly, the plant constituents most often found in classic tonics like licorice, ginseng are plant steroids including saponins, which also have a sweet taste.

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