In the October 2004 issue of BCMJ, the BC Centre for Disease Control reported marked elevation of blood mercury in two preschool aged children of Asian ethnicity with unusually high fish consumption. They recommended physicians providing care for young children and women of childbearing age to inquire as to the frequency and species of fish consumed, and to measure blood mercury in individuals at risk of elevated blood mercury.
There is a recent report of acute generalized dermatitis, abnormal liver function, and elevated blood mercury level (187 nmol/L) associated with Chinese herbal medicine used for rheumatism by an 80-year-old Chinese patient. The elevated blood mercury level returned to normal range upon discontinuation of Chinese herbal medicine, while his diet remained unchanged.
In the traditional Chinese medicine, Chinese herbal medicine, besides herbs, contains animal products and minerals. The minerals include two mercurials, Zhu-Sha/Cinnabar (red mercuric sulfide) to bring longevity, and Qing-Fen/calomel (mercurous chloride) to detoxify various poisonous conditions. Mercury as adulterant or contaminant in Chinese patent medicines of herbal origin has been well documented.[4-6]
The BC Medical Journal and a review article listed the various sources of mercury. They do not include Chinese herbal medicine or Chinese patent medicines of herbal origin.
About 12% of the US population used herbal medicine in 1997, a 380% increase from 1990. Chinese herbal medicine and Chinese patent medicine, purchased in local Chinese herbal shops, are used increasingly by Chinese and other Asians, and by Caucasians as well.
Allergic and adverse reactions have been reported in both Chinese and Caucasian patients seen locally.[2,10-13]
It is important for physicians to ask all patients about their use of complementary and alternative medicine. Blood mercury measurements should be considered in patients with dermatological, neurological, or renal abnormality who are taking Chinese herbal medicine or Chinese patent medicine.
—H.C. George Wong, MD
Division of Allergy and Immunology, UBC,
Vancouver General Hospital,
Alternative therapies and allied health committee, BCMA