Know the Science: How Medications and Supplements Can Interact
Some Supplements May Decrease the Effects of Drugs
Sometimes, taking a drug and a supplement together may decrease the drug’s effects. This means that you aren’t getting the full benefit from the drug that your health care provider wants you to have.

One popular herbal supplement is especially well known for decreasing the effects of drugs. It does this by speeding up the processes in your body that change drugs into inactive substances. This herb may decrease the effectiveness of more than 70 percent of all drugs.
Which of these herbs is the one that decreases the effects of many drugs?
Black cohosh
Echinacea
Saw palmetto
St. John’s wort
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