Dong quai, also known as Chinese angelica and tang kuei, has been used in Traditional Chinese Medicine, or TCM, for thousands of years as a blood tonic and a treatment for symptoms related to menstruation and menopause. While the U.S. Federal Drug Administration classifies this herb as a food ingredient considered GRAS, or Generally Recognized As Safe, dong quai may produce signs of toxicity in some people. Talk to your health care provider before using this herb.
Estrogenic Effects
According to a draft proposal of the July 2009 National Toxicology Program Board of Scientific Counselors Meeting, which outlines the specific aims of future research on dong quai, project leader Michael Wyde asserts that existing clinical studies on the estrogenic effects of this herb are conflicting. Wyde points out that while some studies indicate that dong quai exerts estrogenic activity in rats, other studies appear to demonstrate that ethanol compounds in this herb exhibit anti-estrogen effects as well as counter male hormones. For instance, a paper published in the "Singapore Journal of Medicine" reported on a case of a 35-year old man who developed signs of gynecomastia, which include pain and swelling of the breasts, after taking dong quai supplements. In addition, according to the Sloan-Kettering Cancer Center, dong quai extracts may stimulate growth in human breast cancer cells.
The isoflavones in dong quai exert only mild estrogenic activity. However, if you are undergoing hormone replacement therapy, treatment for a hormone-drive cancer or taking oral birth control medications, you should not take dong quai. If you're a man and experience signs of gynaecomastia, stop using the herb and see your doctor.
Gastrointestinal Distress
Some people have reported experiencing stomach upset, diarrhea, bloating or loss of appetite with dong quai supplementation. If you have any of these symptoms, discontinue use of this herb.
Increased Bleeding
According to the Sloan-Kettering Cancer Center, dong quai may increase the effect of anticoagulant medications, which may increase the risk of bleeding. There is a report of one case involving a 53-year old woman who had been taking a combination herbal formula that included dong quai to address hot flashes. She subsequently suffered a subarachnoid hemorrhage, which means she was bleeding in the subarachnoid space, the area between the brain and the protective membrane covering the brain. When she stopped using the herb, the bleeding subsided. To be clear, dong quai is not necessarily blamed for this incident since a subarachnoid hemorrhage is caused by head trauma or a ruptured blood vessel. However, this event does demonstrate the increased risk of bleeding in certain individuals or under certain circumstances when dong quai is introduced.
Increased Photosensitivity
If you are using dong quai and notice that your skin tends to burn more readily than it used to, then this is a sign that coumarin derivatives in the herb called psoralens are causing photosensitization. Sloan-Kettering Cancer Center states that people undergoing radiation therapy may experience the same side effect.
References
- "NTP Research Concept: Dong Quai"; National Toxicology Program Board of Scientific Counselors Meeting; Michael Wyde, Director, Project Leader; July 23-24 2009
- "Singapore Journal of Medicine"; S Y Goh, K C Loh; Gynaecomastia and the Herbal Tonic Dong Quai; 2001 Vol 42(3) :115-116
- Sloan-Kettering Cancer Center: Dong Quai
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