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St. John's Wort Is Not Necessarily Safer Than Fluoxetine—Commentary

08/24/15 John H. Greist, MD, University of Wisconsin School of Medicine and Public Health|Madison Institute of Medicine;

Depression is a common disorder that causes distress, dysfunction, and sometimes death through suicide. Short-lived depressed mood due to life stresses is even more common, and many people seek relief through use of over-the-counter drugs. Treatment with antidepressants is often effective but also often causes side effects.

St. John’s wort is a popular herbal antidepressant. Although many people believe St. John’s wort is effective for treating depression, the effectiveness is uncertain. Some studies have found that it is as effective as or more effective than typical antidepressants, but other studies have shown that it is less effective. 

Some people believe that natural treatments are more likely to be helpful than synthetic drugs and cause fewer side effects. However, the study reported here found that people who took St. John’s wort to treat depression had the same types of side effects as people who took fluoxetine, a widely used antidepressant. Side effects of St. John’s wort and typical antidepressants are usually mild or moderate but can be severe or life threatening.

The occurrence of significant side effects in people taking St. John’s wort shows that just because a medicine is made from plants doesn’t mean it can’t cause side effects. Many plant-based and other natural medicines also can interact with other drugs a person is taking. Drug interactions sometimes decrease the effectiveness of a person’s other medications or increase the likelihood of side effects. Thus, it is important for people to tell their doctors about all the medications they are taking, including specifically those obtained over-the-counter.

For depression, there are many effective remedies, including medications, although the antidepressant benefits of St. John’s wort remain debatable. Ideally, every person with depression will have a physician who conducts a thoughtful and thorough evaluation before counseling sensible treatment, balancing probable benefit and risk. In reality, many people proceed on their own. For that reason, people should be sure they understand the potential serious risks of self-treatment with St. John’s wort and seek medical care should the herbal remedy not provide rapid relief or cause troubling side effects.

See Dr. Greist's discussion of Anxiety Disorders in The Manuals.