Cool the Blood (liang xue)

Herbs that cool the blood are cold, often bitter, sweet or salty herbs which treat the most serious forms of febrile disease, which has entered the nutritive (ying) or blood (xue) levels, presenting with restlessness, irritability, delirium, changes in consciousness, purpurea and bleeding from various orifices.

Since heat at this level damages the yin, these herbs often have a yin nourishing property too, such as sheng di huang (rehmannia, Rehmannia glutinosa) and xuan shen (figwort, Scrofularia ningpoensis), or can at least be used safely to clear deficiency heat without harming the yin, such as mu dan pi (tree peony root bark, Paeonia suffructicosa), making their applications extend far beyond the treatment of febrile diseases.