The term “dong quai” (a Chinese name that is sometimes transliterated tang-kuei or dang-gui) refers to a plant known either as A. polymorpha var. sinensis or simply as A. sinensis. As the name suggests, this member of the celery family comes out of the traditional Chinese pharmacopoeia.
In China, it is even more widely used than ginseng. It has recently earned itself a considerable following in Australia and the United States.
The root is the part of the plant that is used. Chinese healers make a tea (a “decoction,” more properly speaking) and use it for gynecological disorders such as menstrual cramps or irregular menstrual periods.
But the American baby boomers, with their preference for herbal medicines, have made dong quai especially popular as an alternative to HRT for menopausal women.
At least six chemicals related to coumarin have been identified in dong quai. These include bergapten, imperatorin, oxypeucedanin, osthole, and psoralen.
Coumarin chemicals may act to dilate blood vessels and to relax smooth muscle (antispasmodic). Osthole is also known to stimulate the brain.
No estrogenic constituent of dong quai has been specifically identified, but research by Patricia Eagon of the University of Pittsburgh has shown that dong quai binds to estrogen receptors. Like estrogen, dong quai also promotes the growth of the lining of the uterus in rats.
Research on humans has not confirmed this activity. There is inadequate information to evaluate whether estrogenic activity of dong quai would increase a woman’s risk of breast cancer.
In China, traditional practitioners prescribe dong quai together with other herbs such as Astragalus.
Tests in small animals suggest that dong quai extract may have some effects on immune function, but the actions appear to be complex and in some respects contradictory. These actions, however, might explain why it has been considered a “blood purifier.”
Dong quai has a mildly laxative effect.
At least one of the constituents can stimulate the brain, improving alertness.
Some sources recommend dong quai for the treatment of menopausal symptoms, and women anxious to relieve hot flashes without prescription medications have turned to dong quai as one of the herbal medicines that might help.
A 1997 double-blind, placebo-controlled trial conducted by Kaiser Permanente and published in Fertility and Sterility found, however, that women taking dong quai had just as many hot flashes as women on placebo pills.
Dong quai may be helpful for menstrual cramps, since some components appear to have antispasmodic action. It also dilates blood vessels.
Test tube research suggests that dong quai, in combination with other Chinese herbs, can stimulate the growth of nerve cells. We don’t know whether this would produce a significant benefit in a human being.
The suggested dose is approximately 10 to 40 drops of tincture one to three times daily. It may also be administered as capsules (1,500 mg three times a day in one study) or as a tea.
Different preparations may call for variations on these doses, so read the directions on the packet, or better yet, get personal advice from an experienced practitioner.
Dong quai is expected to provide symptomatic relief rather quickly, perhaps within two weeks or so. Because of the possibility of adverse reactions, long-term use is not recommended.
Pregnant women should avoid dong quai.
This herb is not appropriate for women with heavy menstrual bleeding or fibroids, as it might make these problems worse. Because it is a laxative, women with diarrhea or bloating should refrain from taking it.
According to women’s lore, dong quai works better for intermittent hot flashes than for women who feel hot constantly. The woman who is hot all the time might find that this symptom is exaggerated when she takes dong quai.
The furocoumarin compounds in dong quai, especially psoralen and bergapten, can sensitize the skin to the sun, resulting in a severe sunburn or a rash. By themselves, these compounds are also carcinogenic on exposure to light, and experts in their chemistry recommend that people avoid them if possible.
Certainly anyone taking dong quai should stay out of the sun and avoid tanning lamps even though there are no studies showing that people taking dong quai have experienced photosensitivity reactions.
Dong quai is a laxative. For some people, this will be considered an adverse effect.
Very little information is available on possible interactions of dong quai with prescription or over-the-counter medicines.
Experts on grapefruit chemistry believe that a furocoumarin in grapefruit is responsible for its effect on the enzyme that metabolizes many medications. No one has studied dong quai to see whether its furocoumarins might have a similar impact.
It is not known whether the coumarins in dong quai might interact with the anticoagulant drug Coumadin, itself a coumarin derivative. To be safe, any woman taking both the herb and the prescription medicine should discuss this situation with her doctor and should have bleeding time (PT and INR) checked frequently, especially when starting or stopping the herb.