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The U.S. Food and Drug Administration (FDA) has advised manufacturers of dietary supplements containing comfrey to immediately remove their products from the market and urged consumers to stop using the products. The government contends that the pyrrolizidine alkaloids in comfrey cause liver damage and are possible carcinogens.
At the same time, the Federal Trade Commission (FTC) filed charges against two supplement manufacturers marketing comfrey products on the Internet for making "unfounded claims that the products were beneficial in the treatment of a wide variety of serious diseases and health conditions and that they were safe." Christopher Enterprises Inc. of Springville, UT, and Western Botanicals Inc. of Fair Oaks, CA, agreed to stop marketing the products intended for internal use and on open wounds, the FTC said.
Both companies have agreed to include a warning on any comfrey products intended for topical use: "Warning: External Use Only. Consuming this product can cause serous liver damage. This product contains comfrey. Comfrey contains pyrrolizidine alkaloids, which may cause serious illness or death. This product should not be taken orally, used as a suppository, or applied to broken skin."
Comfrey falls into a gray area in terms of safety and efficacy, says Christopher Hobbs, LAc, AHG, a fourth-generation herbalist and botanist who practices in Williams, OR. The FDA and FTC actions are overreactions, contends Hobbs. "Millions of people have used comfrey and there have only been a few reports of adverse events - of the three or four that were reported in the Journal of the American Medical Association seven or eight years ago, all are questionable. If the safety issue is all that serious, why didn’t they take this action sooner?" asks Hobbs.
"It’s the same old thing of throw everything out because of one toxic compound. It’s a double standard, since numerous foods have toxic compounds, too," says Hobbs.
Yet, some herbalists are willing to make comfrey a "sacrificial lamb," says Hobbs, because there is little scientific evidence of its efficacy, and although it may be effective for numerous ailments, it is not irreplaceable in the herbal pharmacopeia. "So there wasn’t much of a fight, and that’s of concern to me, because it seems like there’s a concerted campaign in the news media to discredit herbs," Hobbs says. "Herbs are a multi- billion dollar industry that is taking away income from pharmaceutical companies."
The FDA declined to provide an official to be interviewed for this article, instead referring the writer to the published letter and news release.
Several people have become ill from taking comfrey as a dietary supplement or as a tea in the past four years, Christine Lewis, PhD, director of the FDA’s office responsible for dietary supplements, wrote in a news release. There have been no reported deaths, Lewis said. "It is a dangerous substance and we don’t think it should be marketed," she added.
No specific evidence of comfrey’s toxicity was attached to the letter sent to major herb and supplement associations. (See "Highlights of the FDA letter," in this issue.) Comfrey is widely available and is commonly used topically as a salve or cream for sprains, bruises, wounds, and broken bones. It is used internally in the form of pills or teas for cough, stomach ulcers, and as an overall tonic. In fact, as Complementary Therapies in Chronic Care goes to press, the popular Internet vitamin retailer VitaminShoppe.com, offered two capsule supplements containing comfrey and two creams.
Hobbs’ opposition to the FDA and FTC actions is more a matter of principle than one of great affection for comfrey. "I don’t recommend using the root of comfrey, and the leaves are most often used externally for bites and stings," says Hobbs. "It’s not something you would use continually for a long period of time."
While roots and fresh young leaves may have high concentrations of pyrrolizidine alkaloids, mature leaves contain very few pyrrolizidine alkaloids, according to British research.1
(For more information, go to the Food and Drug Administration’s web site: http://vm.cfsan.fda.gov.)
1. Winship KA. Toxicity of comfrey. Adverse Drug React Toxicol Rev 1991; 10:47-59.