Widely used in Chinese herbal medicine, the herb corydalis is said to alleviate pain by “moving qi” and “stimulating the blood.” These expressions refer to traditional concepts included within the complex theories of traditional Chinese herbal medicine. In terms of Western diagnostic categories, corydalis may be recommended forsoft tissue injuries, menstrual discomfort, and abdominal pain.

The part of the plant used medicinally is the rhizome (underground stalk).

There is no reliable evidence that corydalis or its constituents offer any medicinal benefits. Corydalis contains a number of active and potentially dangerous chemicals in the alkaloid family, including tetrahydropalmatine (THP), corydaline, protopine, tetrahydrocoptisine, tetrahydrocolumbamine, and corybulbine. Of these, THP may be the most active, as well as the most toxic (see Safety Issues).

Only double-blind, placebo-controlled studies can actually show that a treatment works, and there is only one such study that is relevant to corydalis. This trial tested THP as a treatment for a type of heart rhythm abnormality called supraventricular arrhythmia.1Reportedly, use of THP produced significant benefits as compared to placebo. However, this study was conducted in China, and there is considerable skepticism about the validity of Chinese medical trials.2 (For information on why double-blind studies are essential, see Why Does This Database Rely on Double-blind Trials?)

Much weaker evidence from animal and test-tubestudies hint that TNP or corydalis extracts might have pain-relieving, sedative, and anti-inflammatory effects.3-5Corydalis constituents may also affect neurotransmitters in the brain, including dopamine and GABA.6-7 Equally weak evidence hints at benefits for preventing or treating cataracts,8reducing blood coagulation,9 and lowering blood pressure.10 However, none of this research remotely approaches the level of evidence that can prove a treatment effective.