The National Center for Complementary and Integrative Health, a division of the National Institutes of Medicine, estimates that about 38% of American adults use complementary and alternative medicine.1 That statistic includes 17.7% who say they use natural products. Despite their popularity, many physicians remain skeptical—and for good reason. Enthusiasts frequently offer dramatic anecdotes to “prove” their supplements' worth, but little scientific support is available for most herbal remedies. There are, however, exceptions. As this review of the medical literature will reveal, there is evidence to support the use of capsaicin to relieve osteoarthritis (OA) and postherpetic neuralgia (PHN) and support for green tea to serve as a lipid-lowering agent and help treat diabetes. Similarly, researchers have found that peppermint may be of value in the management of irritable bowel syndrome (IBS). (We also review the literature on butterbur for migraine headaches, but serious safety issues exist; TABLE.)
In the second part of this series, which is available here, we explore what the evidence tells us about the use of turmeric, chamomile, rosemary, coffee, and cocoa.
Worth noting as you consider this—or any—review of herbals is that while there is limited scientific evidence to establish the safety and efficacy of most herbal products, they are nonetheless freely sold without US Food & Drug Administration (FDA) approval because under current regulations, they are considered dietary supplements. That legal designation means companies can manufacture, sell, and market herbs without first demonstrating safety and efficacy, as is required for pharmaceutical drugs. Because herbal medications do not require the same testing through the large randomized controlled trials (RCTs) required for pharmaceuticals, evidence is often based on smaller RCTs and other studies of lower overall quality. Despite these limitations, we believe it’s worth keeping an open mind about the value of evidence-based herbal and botanical treatments.