Saint John's wort
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Alprazolam, trade name Xanax, is prescribed for treatment of anxiety and panic disorders. The website Psych Central reports that Xanax was the number one prescribed psychiatric drug in the United States in 2009, with over 44 million prescriptions for the drug written that year. If you take Xanax, you should avoid taking herbs that may interfere with the drug's performance, or cause harmful side effects.

Milk Thistle

If you take the herbal remedy milk thistle, most commonly used to protect the liver, you should avoid taking Xanax at the same time. According to the University of Maryland Medical Center, milk thistle is broken down by the same liver enzymes that break down Xanax. Taking both Xanax and milk thistle at the same time could limit the effectiveness of the drug.

Kava Kava

Kava kava (Piper methysticum) is said to promote relaxation and relieve anxiety. Available in teas, tablets or tinctures, it is also promoted as a remedy for insomnia. Avoid taking kava kava if you are also taking Xanax, as the herb may magnify the effects of Xanax. The University of Maryland Medical Center cautions against taking any dosage of kava kava without a doctor's supervision--with or without Xanax--since some people have suffered liver damage due use of this remedy.


The herb valerian has a mild sedative effect and is sometimes taken as a remedy for insomnia or to promote general relaxation. You may purchase valerian in teas, capsules or tinctures. Because valerian is a sedative, it could magnify the sedative effects of Xanax if the herb and the drug are taken together. This could repress breathing and result in loss of consciousness or even death.

St. John's Wort

St. John's wort has been touted as an herbal remedy for depression. When combined with Xanax, St. John's wort may increase the sedative effects of Xanax.