National Center for Complementary and Integrative Health (NCCIH)

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Josephine P. Briggs, M.D.
Josephine P. Briggs, M.D.

Director’s Page
Josephine P. Briggs, M.D.

What We Don’t Know About Supplement-Drug Interactions

September 17, 2015

Many Americans use dietary supplements as part of their daily health regimen. In fact, a recent national survey found that in 2012, natural products (nonvitamin, nonmineral dietary supplements) were the most frequently used complementary health approach among adults and children. Almost 18 percent of adults and about 5 percent of children use natural products.

While there has been research that suggests health benefits of some dietary supplements, there is also a concern about the safety of some products, including the potential for interactions with drugs.

Interactions may occur between prescription drugs, over-the-counter drugs, dietary supplements, and even small molecules in food—making it a daunting challenge for scientists to identify all interactions that could be harmful. The bottom line here is that there’s a lot we don’t know and much more study needed. However, attention must be paid to a few herbs such as St. John’s wort and goldenseal, and a few others, which have a high risk of potential interactions with certain drugs. A new module to help understand these types of interactions is now available on our Web site.

In addition, we’ve just announced an award to the University of Washington for a new Center of Excellence, whose goal is to provide leadership on how best to study potential adverse interactions between natural products and conventional medications. The data generated by the Center’s research projects will be collected in a repository and Web-based portal so that researchers can further analyze the data and communicate their results to health care providers and to the public. It’s very exciting and important work that will shed more light on the risks of interactions between natural products and conventional medicines.

As scientists continue to gather more information on interactions, it’s important to talk with your health care providers and tell them about all the drugs and supplements you take. Often, when you visit a health care provider for the first time, you fill out a form that asks you to list all the drugs and supplements you take. Be sure to update this information every time you visit the provider’s office. Take care, and be well!

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