Tell me about...

Corydalis (yan hu suo)

What is corydalis? What is it used for?

Corydalis is a tall, thin herb native to the Zhejiang province of China. The plant consists of a thin, green stem with green leaves and yellow flowers. The rhizome is used for medicinal purposes.

In traditional Chinese medicine, corydalis is believed to invigorate the blood, facilitate the movement of qi throughout the body, and reduces menstrual, abdominal and hernial pain.

To date, a total of 20 alkaloids have been isolated in corydalis, the most powerful of which is a compound called tetrahydropalmatine (THP). Lab tests have shown that THP acts as an analgesic and sedative and can have a wide range of actions on the central nervous system. Animal studies have found that THP decreases the stickiness of platelets, which helps protect against heart attacks and strokes, and can lower heart rate and blood pressure. Human trials have found that THP can help people with insomnia fall asleep easier, without any adverse side effects, and a Chinese study conducted in 1990 found that HTP could reduce nerve pain and pain associated with menstruation.

How much corydalis should I take?

The recommended dosage for corydalis is 5-10 grams per day of the dried rhizome. Some practitioners recommend an alternative of 10-20 millileters of an extract daily as an alternative.

What forms of corydalis are available?

Many Asian markets and specialty stores sell dried or powdered corydalis root. Corydalis is also available as a tablet or as an alcohol-based extract.

What can happen if I take too much corydalis? Are there any interactions I should be aware of? What precautions should I take?

The American Herbal Products Association has assigned corydalis a class 2B rating, meaning that it should not be taken by pregnant or nursing women. Some individuals who take large doses of corydalis may experience vertigo, fatigue or nausea. In addition, there have been many reports of subjects experiencing THP toxicity, which could lead to hepatitis.

At present, there are no known drug interactions with corydalis.

More links

References

• Bensky D, Gamble A, Kaptchuk T. Chinese Herbal Medicine Materia Medica. Vista, CA: Eastland Press, 1993:270.
• Lin MT, Chueh FY, Hsieh MT et al. Antihypertensive effects of dl-tetrahydropalmatine: an active principle isolated from corydalis. Clin Exper Pharm Physiol 1996;23:738—42.
• Xiaolin N, Zhenhua H, Xin M, et al. Clinical and experimental study of dl-tetrahydropalmatine effect in the treatment of supraventricular arrhythmia. J Xi'An Med Univ 1998;10:150—3.
• Xing JF, Wang MN, Ma XY, et al. Effects of dl-tetrahydropalmatine on rabbit platelet aggregation and experimental thrombosis in rats. Chin Pharm Bull 1997; 13:258—60.
• Zhu YP. Chinese Materia Media: Chemistry, Pharmacology, and Applications. Australia: Harwood Academic Publishers, 1998:445—8.