What Herbs May Help People With Anxiety-By Michael Kahn, M.D., Harvard Medical School

Frequently, patients ask me about various herbal remedies and supplements for treating anxiety. It’s no secret that these remedies are popular in this country. But do they work?

Here’s a rundown on the latest evidence for and against several natural remedies. It is based on a review published in 2007 in American Family Physician and reported by the Harvard Women’s Health Watch:

Kava (Piper methysticum). Usually prepared as a tea, kava is made from the dried rhizome (root) of a shrub found throughout the South Pacific, where it is used for social, ceremonial, and medicinal purposes. Kava is reported to have a relaxing effect without impairing mental and physical function. Several randomized controlled trials have shown that kava is slightly superior to a placebo in relieving anxiety. One trial indicated that it was as effective as the anti-anxiety drug buspirone (brand name: Buspar).

Kava inhibits an enzyme used by the liver to metabolize several medications, so it’s important to consider possible drug interactions before using this herb. Do not take alcohol, barbiturates, benzodiazepine drugs, or alprazolam (Xanax) while taking kava. You should not take kava if you have liver problems.

Kava should not be used for longer than four months because its health effects beyond that haven’t been established. With long-term use, a rash or skin yellowing may develop, but these symptoms usually go away when you stop taking the herb. Rare cases of serious liver disease have led several countries to ban kava, but it remains available in the United States. (The FDA has issued warnings but questions the accuracy of the liver toxicity reports.)

As with many herbs, different plant parts can have different types of activity; it may be that some preparations are potentially more harmful to the liver than others. Look for supplements made from the root (rhizome) rather than the leaves or stems.

Inositol. This supplement, a member of the B-vitamin complex, has been found somewhat helpful for the treatment of panic disorder in two controlled trials. One study showed that inositol was superior to a placebo in reducing symptoms. The other found it to be as effective in treating panic disorder as the selective serotonin reuptake inhibitor (SSRI) fluvoxamine. The side effects are mild and similar to those of SSRIs. Results of studies for obsessive compulsive disorder have been mixed.

St. John’s Wort (Hypericum perforatum). No controlled trials have found that St. John’s wort has any beneficial effects on generalized anxiety disorder, post-traumatic stress disorder, obsessive compulsive disorder, or any other anxiety disorder. (The evidence favoring its use in mild-to-moderate depression is better.)

Drug interactions can be a problem with St. John’s wort. It interferes with the activity of many drugs, including carbamazepine (an anti-epileptic drug), cyclosporine (an anti-rejection medication), the anticancer drug irinotecan, birth control pills, simvastatin (a statin), antidepressants, the blood-thinner warfarin, and digoxin (a heart drug).


To sum up, there is good evidence that kava can help in treating mild to moderate symptoms of anxiety disorders in people who are not using alcohol or taking medications metabolized by the liver. There is some evidence for inositol in treating panic disorder and possibly obsessive compulsive disorder. There’s not enough evidence to recommend that people with anxiety disorders take St. John’s wort.

Herbal medicines and dietary supplements are not regulated as drugs, so their safety and effectiveness are not established. And there’s no guarantee that you’re getting exactly what appears on a supplement’s label. Herbal supplements in particular can have many active constituents, not all of which have been tested or even identified. If you’re considering an herbal or dietary supplement to treat symptoms of anxiety (or any other condition, for that matter) discuss it with your clinician first.