English: Swallow-wort roots

Chinese: 白薇

Parts used: Dried root and rhizome

TCM category: Herbs that clear Heat and dry Dampness

TCM nature: Cold

TCM taste(s): BitterSalty

Organ affinity: Kidney Liver Stomach

Scientific name: Cynanchum atratum or Cynanchum versicolor

Other names: Dog-strangling vine, Cynanchi, Blackend swallowwort

Use of Bai Wei (swallow-wort roots) in TCM

Please note that you should never self-prescribe TCM ingredients. A TCM ingredient is almost never eaten on its own but as part of a formula containing several ingredients that act together. Please consult a professional TCM practitioner, they will be best able to guide you.

Preparation: Remove impurities, wash, cut into sections and dry.

Dosage: 3 - 9 grams

Main actions according to TCM*: Cools the Blood and expels Deficient Heat. Clears Heat in the Blood by encouraging urination. Detoxifies when used either internally or externally.

Primary conditions or symptoms for which Bai Wei may be prescribed by TCM doctors*: fever Strangury Carbuncles Sores Urinary tract infection Sore throat Hematuria Snake bites

Contraindications*: This herb should not be used by those with diarrhea or those with no true Heat signs.

Common TCM formulas in which Bai Wei is used*

Er Qing Gao

Source date: 1617 AD

Number of ingredients: 11 herbs

Formula key actions: Clears Toxic-Heat. Disperses swelling. Relieves pain.

Conditions targeted*: BoilsCarbuncles and others

Bai Wei is a deputy ingredient in Er Qing Gao. This means it helps the king ingredient(s) treat the main pattern or it serves to treat a coexisting pattern.

In Er Qing Gao, Bai Wei is bitter and cold. It drains Fire, resolves Toxic-Heat, disperses swelling and relives pain. It treats internal clumping due to accumulation of Toxic-Heat. 

Read more about Er Qing Gao

Jia Jian Wei Rui Tang

Source date: Qing dynasty

Number of ingredients: 8 herbs

Formula key actions: Nourishes the Yin. Clears Heat. Induces Sweating. Releases the Exterior.

Conditions targeted*: Common coldAcute tonsilitis and others

Bai Wei is an assistant ingredient in Jia Jian Wei Rui Tang. This means that it either serves to reinforces the effect of other ingredients or it moderates their toxicity.

In Jia Jian Wei Rui Tang, Bai Wei cools the Blood and clears Heat without injuring the Yin. Thus it treats the thirst and irritability.

Read more about Jia Jian Wei Rui Tang

Key TCM concepts behind Bai Wei's properties

In Traditional Chinese Medicine (TCM), Bai Wei belongs to the 'Herbs that clear Heat and dry Dampness' category. Herbs in this category are used to clear inflammatory and infectious conditions, referred to as 'Internal Heat' in TCM. This is why most of the herbs in this category will have both antibacterial and antiviral properties. In TCM one has too much 'Internal Heat' in their body as a result of a deficiency of 'Yin' (which is Cold in nature, see our explanation on Yin and Yang) or, more commonly, an Excess of Yang (Hot in nature). Herbs that clear Heat and dry Dampness treat the latter while, at the same time, relieving the body of excess Dampness. As such they tend to be Cold or Neutral in nature.

As suggested by its category Bai Wei is Cold in nature. This means that Bai Wei typically helps people who have too much 'Heat' in their body. Balance between Yin and Yang is a key health concept in TCM. Those who have too much Heat in their body are said to either have a Yang Excess (because Yang is Hot in nature) or a Yin deficiency (Yin is Cold in Nature). Depending on your condition Bai Wei can help restore a harmonious balance between Yin and Yang.

Bai Wei also tastes Bitter and Salty. The so-called 'Five Phases' theory in Chinese Medicine states that the taste of TCM ingredients is a key determinant of their action in the body. Bitter ingredients like Bai Wei tends to have a cleansing action on the body by clearing Heat, drying Dampness and promoting elimination via urination or bowel movements. On the other hand Salty ingredients tend to have a draining effect in the body because they clear accumulations, remove Phlegm and soften hard lumps.

The tastes of ingredients in TCM also determine what Organs and Meridians they target. As such Bai Wei is thought to target the Kidney, the Liver and the Stomach. According to TCM, the Kidneys do not only regulate the urinary system but also play a key role in the reproductive system and the growth and aging process of the body. The Liver on the other hand is often referred as the body's "general" because it is in charge of regulating the movements of Qi and the Body Fluids. It also takes a leading role in balancing our emotions. The Stomach is responsible for receiving and ripening ingested food and fluids. It is also tasked with descending the digested elements downwards to the Small Intestine.

Research on Bai Wei

The extract of blackend swallowwort root can up-regulate the expression of vascular endothelial growth factor –C (VEGF-C), VEGF-A and lymphatic vessel endothelial HA receptor-1, to promote liver angiogenesis of mice with partial hepatectomy.1


1. Meng F. (2015) The extract of blackend swallowwort root up-regulates the expressions of angiogenesis related proteins and promotes liver angiogenesis of mice with partial hepatectomy. Xi Bao Yu Fen Zi Mian Yi Xue Za Zhi 31(4): 478-83