Thuja

Thuja may be used to treat viral infections affecting the skin, respiratory and other body systems.  It has been shown to be active against herpes and other viruses including some strains of influenza.  Internally, it may be given together with other herbs such as echinacea (Echinacea angustifolia) and wild indigo (Baptisia tinctoria) as a preventative medicine or to treat chronic viral conditions (1). Thuja can be prescribed for respiratory conditions, owing to its qualities as as a stimulating expectorant, diaphoretic and immune tonic.

The combined alterative, antimicrobial, antifungal and diuretic properties are helpful in treating a range of skin conditions including tinea, ringworm, eczema, and psoriasis. Thuja is commonly used topically, being applied repeatedly in tincture form onto warts and verrucas. It can be similarly applied to nasal polyps or taken internally to reduce fibroids and other growths (2). It is used for treating virally induced cancers, such as squamous cell in the mouth and throat, cervical cancer, melanoma, and lymphoma. Thuja can also be applied for pelvic and reproductive system cancers(3).

Thuja stimulates smooth muscle in the heart, bladder and uterus, improving muscle tone in the urinary system and treating incontinence where this is the cause. It can also stimulate uterine contractions in cases of amenorrhoea (4).

The thuja tree, when mature, gives a sense of strength and permanence. It has a strong presence, the wood is rot-resistant and the oil is powerful against pathogens. Although rarely so long-lived, some trees in North America have been found to be over 800 years old and a few well over 1,000 (5). The branches spread almost horizontally and are thickly layered so that the reddish trunk is almost hidden, giving a sense of its protective nature and strong defense.

A spicy insect repellent aroma comes from the leaves. Repeated handling of the foliage can irritate the skin, with a place in poison guides,due to the thujone content of the essential oil, thuja deserves respect and care in medicinal use (6).

It is thanks also to the power of the essential oil that thuja has become a familiar part of many herbal treatments and is featured in ongoing research. Looked upon as a systemic resolvent in cases of lymphatic stagnation, it is valued in skin and mucosal conditions alike (7).

In the 18th century in the Quebec area of its native Canada, thuja leaves were pounded in a mortar with grease and the mix boiled to make a salve which was spread on linen and applied to relieve rheumatic pain. The Iroquois people used thuja to treat coughs and the decoction was taken to relieve intermittent fevers near Saratoga (8).

The Eclectic physicians used thuja to treat multiple conditions. Ellingwood gives a long and enthusiastic entry peppered with examples of cases treated. He advises beginning with a small dose which might be raised as necessary. He presents thuja as a herb to be used, among other conditions, for gangrenous ulcers, treating blood dyscrasias and abnormal growths of the skin or mucous membranes (9). Thuja was listed in the US Pharmacopoeia from 1882–1894 as a uterine stimulant and diuretic (10).

Physio-medicalists in America widened the use treating several cancers, amenorrhoea and venereal warts with thuja preparations. They continued native American use as a counterirritant for rheumatism and pain and combined thuja and witch hazel (Hamamelis virginiana) to relieve eczema (11). In Britain it was included in the Extra Pharmacopoeia of 1885 and 1892 as being used to remove warts and fungoid granulations from ulcers. Internal use was for amenorrhoea, pulmonary catarrh, and worms (12). Early use to counteract the effects of the smallpox vaccination has been repeatedly referred to (13,14,15).

In summary, thuja has had a wide range of traditional uses in treating mucosal conditions including bronchial catarrh and intermittent fevers. Tincture from the bark as well as from the leaves has been applied to remove small warts, the treatment sometimes lasting several weeks (16).  Additionally, urinary problems such as enuresis, cystitis, and urethritis, have all benefitted from thuja. Most frequent are references to treatments for skin conditions such as psoriasis. The herb or tincture has been applied topically for fungal skin infections, skin ulcers, and carcinomatous ulcerations. The stimulant effect on the uterus has meant thuja has been prescribed to treat amenorrhea (2). Thuja was also used to treat uterine cancer by Eclectic physicians(13). 

Cardiovascular system

Several authors comment on the stimulating action of thuja for the heart muscle and it appears in the British Herbal Pharmacopoeia as specifically indicated in bronchitis with cardiac weakness, for this reason (14).

Immune system

Thuja offers support to the immune system against pathogens due to its antiviral, antibacterial and antifungal roles (15). It is seen as a key herb for treating chronic viral infections (1). Thuja and echinacea may be the most important herbs for adjuvant treatment of infectious diseases and colds with research supporting these applications (16).

Nervous system

Thuja has long been seen as a nervine and was used alongside oatstraw (Avena sativa) to support the nervous system  (11). More recently it has been classified as a nervine with tonic and stimulant actions (11,13,15).

Reproductive system

Thuja stimulates uterine muscles which is the reason for its contraindication in pregnancy, as this may cause abortion. This stimulant action is useful in treating amenorrhoea and thuja has had further traditional use in treating uterine carcinomas. It is recommended for reducing the size of fibroids and lesions in endometriosis. It is also  prescribed for reducing prostatic enlargement (2,15).

Respiratory system

Hoffmann suggests painting nasal polyps daily with the fluid extract of thuja, in combination with a nasal snuff to shrink them (4). Thuja is listed as a stimulant to mucous and serous membranes with an expectorant action. This also recommends the herb for treating sinusitis (15,2) .

Musculoskeletal system

The traditional use as an analgesic for rheumatic and arthritic pain is still relevant today (17). It is indicated more specifically for the extreme pain from sensitivity in gout, and thuja has been combined with other herbs such as burdock root (Arctium lappa), celery seed (Apium graveolens) and yarrow (Achillea millefolium) to provide relief (4). 

Skin 

Hoffmann suggests thuja as an antimicrobial application for use in eczema and itchy skin conditions, such as psoriasis (4). Molluscum contagiosum, tinea, warts and verrucas are also addressed by the antiviral properties of thuja (15). Thuja can be used in salves for healing wounds, bedsores, and cancerous ulcers.  

Urinary system

Thuja has traditional recognition as a diuretic with a strong influence on the urinary system and has been prescribed for urinary infections, bed-wetting and urethritis. In the case of treating urinary incontinence, the effect is most helpful when it is due to lack of muscle tone (13,15,2).

Thuja occidentalis (Arbor vitae): A review of its pharmaceutical, pharmacological and clinical properties 

There have been many reviews of the mode of action of thuja, but no controlled trials of the herb when used alone. Clinical studies have used extracts of Thuja occidentalis and other immunostimulants, demonstrating safety in respiratory tract infections. In vitro and in vivo studies have shown the antiviral and immunostimulant effects with cytokine and antibody production and activation of macrophages. Mice have commonly been used for in vivo trials, rats and rabbits less often. More clinical studies are indicated and needed. Several studies have looked at use of thuja and its antimetastatic action (18).

Effect of Thuja occidentalis and its polysaccharide on cell-mediated immune responses and cytokine levels of metastatic tumor-bearing animals

In this article, mice were administered with thuja occidentalis extract and its polysaccharide (TPS) to test the ability of the immune cells to maintain antitumour activity in the microenvironment of a metastatic tumour. Metastasis was injected into a tail vein of each mouse and effector mechanisms studied. The effect of Thuja occidentalis extract and TPS on pro-inflammatory cytokines and tissue inhibitor matrix metalloproteinases (TIMP) levels were also analysed.

It was found that the actions of natural killer (NK) cells were enhanced and antibody-dependent cell and complement-mediated cytotoxicity increased earlier than in control animals. Additionally, pro-inflammatory cytokines were lowered and anti-tumour factors elevated by the treatment with thuja. It was concluded there were clear indications that Thuja occidentalis and TPS were effective at stimulating the cell-mediated immune system and decreasing inflammation as well as inhibiting metastasis of tumour cells (19).

A further area of pertinent interest for prescribing thuja is in actions within the reproductive system. The following research, although on rats and using the essential oil and α-thujone rather than orally administered extract of thuja, may give some indication of support for the current practice of treating polycystic ovary syndrome (PCOS) by herbalists.

Thuja occidentalis L. and its active compound, α-thujone: Promising effects in the treatment of polycystic ovary syndrome without inducing osteoporosis

Rats with letrozole-induced PCOS received the oil of Thuja occidentalis and its constituent α-thujone for 21 days. They were then sacrificed and blood samples were taken by cardiac puncture.

The results of testing demonstrated that estradiol and progesterone levels significantly increased, while luteinizing hormone (LH) and testosterone levels decreased in the T. occidentalis- and α-thujone-administered groups. The plasma low-density lipoprotein-cholesterol (LDL-C), leptin, and glucose concentrations were also significantly decreased in the T. occidentalis and α-thujone groups when compared to the control group. Histopathological findings demonstrated that the T. occidentalis and α-thujone groups displayed good healing. It was concluded that T. occidentalis oil and α-thujone  can be used for the treatment of PCOS without inducing osteoporosis (20).

Antidiabetic activity of Thuja occidentalis Linn.

In this study shade dried aerial part (twigs) of Thuja occidentalis were extracted in ethanol. Phytochemical investigations showed the presence of flavonoids (quercetin, kaempherol), tannic acids, polysaccharides and proteins. Wistar albino rats of either sex, weighing 175–220 g, were used. The animals were maintained as per the norms of IAEC and the experiments were cleared by IAEC and the local institutional ethical committee.

The animals were fasted for 18 hours and had induced diabetes by alloxan monohydrate (150 mg/kg, i.p) dissolved in sterile normal saline. Their diabetic state was confirmed when the blood sugar value was greater than 180 mg/dl. All the animals were randomly divided into the four groups with six animals in each group. Group A, B, and C were given vehicle, diabetic and standard drug (glibenclamide, 10 mg/kg per day p.o) control, respectively.

Treatment with the ethanolic fraction of thuja was started 48 hours after the alloxan injection. Blood samples were drawn at weekly intervals until the end of study (i.e. 3 weeks). Fasting blood glucose, blood glutathione estimation and body weight measurement were done on days 1, 7, 14 and 21 of the study. On day 21, blood was collected by cardiac puncture under mild ether anaesthesia from overnight fasted rats and fasting blood sugar was estimated. 

Serum cholesterol, serum triglycerides, serum LDL, serum creatinine, serum urea and serum alkaline phosphatase levels were decreased significantly, and serum HDL levels were increased significantly in both standard and test drug. The conclusion drawn from the study was that it indicated the ethanolic fraction of Thuja occidentalis had shown good antidiabetic activity, with significant antihyperglycemic activities in alloxan induced hyperglycemic rats without significant change in body weight.  It further showed improvement in the lipid profile along with serum creatinine, serum urea and serum alkaline phosphatase by enhancing the effect on cellular antioxidant defences to protect against oxidative damage  (21).

There are five types of thuja, with T. plicata also having been investigated for medicine. Thuja plicata was known as the grandmother of the forest as it was often the oldest tree in the area. Such older trees have a huge capacity for photosynthesis and make more sugars than they need. They channel this extra food via the mushroom mycelium to nearby saplings, feeding them as a grandmother might care for her grandchildren (3).

Thuja occidentalis is native to Northeastern America, and Southeastern Canada. It extends from the Gulf of St Lawrence to the southern part of James Bay and through central Ontario to southeastern Manitoba; then south and east to New Hampshire, and Maine. The species also grows locally in northwestern Ontario, west-central Manitoba, southeastern Minnesota, southern Wisconsin, north-central Illinois, Ohio, southern New England, and in the Appalachian Mountains.  It is also recorded growing in Siberia. 

Thuja grows well in a variety of soils with neither soggy nor very dry conditions. It is found in pastures and cool, moist sites which are nutrient rich. Growing both in fen areas and on loam over limestone or sandstone cliffs, the trees thrive in a neutral or slightly alkaline environment. The tree can be found up to 600 m above sea level (29).

Thuja occidentalis is not on the CITES endangered species list. 

Thuja occidentalis is ranked as G5, secure, on Nature Server. [checked 2016] (30) 

It is not listed on TRAFFIC. 

IUCN listed Thuja occidentalis as least concern in 2011 (31)

However, an article from the Northern Journal of Applied Forestry written in 2009 on northern white-cedar ecology and silviculture in the northeastern United States and southeastern Canada states that white cedar sustainability is a concern due to regeneration failures, difficulty recruiting seedlings into sapling and pole classes, and harvesting levels that exceed growth. The authors conclude that because management of this resource has proven difficult, northern white-cedar silvicultural guidelines are needed throughout its range (32)

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 is 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.

Herbal medicines are often very safe to take; however, their safety and efficacy can be jeopardised by quality issues. So, it is important to buy herbal medicines from a reputable supplier, from sources known to test their herbs to ensure there is no contamination, adulteration or substitution with incorrect plant matter, as well as ensuring that recognised marker compounds are at appropriate levels in the herbs.

Some important quality assurances to look for are certified organic labelling, the correct scientific/botanical name, and the availability of information from the supplier about ingredient origins. A supplier should be able to tell you where the herbs have come from, what contaminants are not in the herb, and what the primary compounds are.

It should be remembered that a full-size tree takes up a wide space in a garden. Thuja can be grown from seed sown in autumn or stratified before sowing (32). Grow in moist but well drained soil, being careful to protect young trees from drying winds. Trees are readily propagated by layering which can happen naturally in their native situation as branches lean down and root. Layering can be done in autumn or spring, or cuttings taken in September and planted in shade (26).

Thuja prescription

The following prescription (100 ml) was given to treat a patient after her annual Pap smear showed cervical atypical squamous cells of undetermined significance. The treatment plan also included dietary advice and the suggestion of relaxation activities. The patient complied with the treatment and a repeat test after three months showed a normal result.

Prescription ingredients

• 40 ml Echinacea spp.                                          
• 20 ml Glycyrrhiza glabra                                                
• 20 ml Hypericum perforatum                                    
• 15 ml Melissa officinalis
• 5 ml Thuja occidentalis     

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