Confusion About Herbal Safety: What You Really Need to Know


IstockphotoLast year, researchers at the Mayo Clinic studied the potential for interactions between dietary supplements and prescription meds. After reviewing surveys taken from 1,795 Mayo Clinic patients, heres how the researchers summarized what they learned:

  • Despite a high prevalence of potential interactions between dietary supplements and prescription medications, the actual potential for harm is low.
  • A small number of prescription medications and dietary supplements account for most potential interactions.
  • Antithrombotic medications (these are anticoagulant and antiplatelet meds such as warfarin and Plavix) were most likely to interact with dietary supplements.

Potential for harm is low.
Few factors account for most interactions.
With these conclusions in mind, I was stunned to read this months report in the Mayo Clinic Health Letter titled, “Herbal Supplements: Risks to Your Health.” It warns that a few supplements “can cause life-threatening problems such as liver damage, uncontrolled bleeding, or heart arrhythmias.”

The story goes on to say that “some common herbs are known to seriously alter the effect of other drugs you may be taking and can also impact the safety of a surgical procedure.” Sounds pretty scary to me.

Which Mayo Clinic should you believe?
The contradiction begs this question: Dont the good people at the Mayo Clinic talk to each other? Whered the writers at the Health Letter get their facts, if not from their very own researchers?

Today, more than two-thirds of Americans take dietary supplements, a broad category which, according to the Food and Drug Administration, includes vitamins, minerals, amino acids, substances that supplement the diet by increasing the total dietary intake (e.g., enzymes or tissues from organs or glands), as well as concentrates, metabolites, constituents, and extracts, in addition to herbs. So were absolutely right to be concerned about safety, including possible drug interactions.

But as the Mayo researchers note, “Distinguishing between a real potential for harm and a purely speculative interaction is important.” What they didnt say: Distinguishing scary headlines from the facts—thats important too.

Seek wise counsel when using herbs
If youd like to treat a chronic or acute health problem with herbs, seek out a physician or licensed healer whos been trained in their use. Ask her about interactions with any drugs you may be taking, and especially ask whether concerns are based on evidence or theoretical speculation. An experienced, well-trained healer prescribing herbal medicine will know the difference, and can offer you the best advice.

Many medical schools now offer courses that cover herbal medicine, so ask your regular doc what his or her experience may be. Most licensed acupuncturists and all practitioners of traditional Chinese medicine study herbs. (Find one at Naturopaths who graduate from four-year postgraduate schools of naturopathy receive a thorough herbal education. (Find one at And members of the American Herbalist Guild take a comprehensive exam testing their herbal knowledge; many members have advanced degrees in other healing disciplines. (Find one at