Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link



Laura Shane-McWhorter

, PharmD, University of Utah College of Pharmacy

Last full review/revision Jul 2020| Content last modified Jul 2020
Click here for the Professional Version

Kava comes from the root of a shrub that grows in the South Pacific. It is ingested as a tea or in capsule form. The active ingredients are thought to be kavalactones.

Medicinal claims

People use kava mostly to reduce anxiety, restlessness, or stress and to aid sleep. Some people use kava for asthma, menopausal symptoms, and urinary tract infections. Some scientific evidence supports use of kava to reduce anxiety and as a sleep aid.

Possible side effects

Some people in both Europe and the United States who have taken kava developed liver toxicity (including liver failure). Thus, the Food and Drug Administration (FDA) has required a warning label on kava products, and safety is under continuing surveillance. Some researchers believe the liver toxicity may be due to inappropriate preparation or poor quality raw material contaminated with mold that contains liver toxins.

When kava is prepared traditionally (as tea) and used in high doses or over long periods of time, a scaly rash (kava dermopathy), vision problems, changes in blood (such as an increased number of red blood cells), and changes in movement disorders (such as worsening of Parkinson disease) may occur.

Possible drug interactions

Kava may prolong the effect of other sedatives (such as barbiturates) and affect driving or other activities requiring alertness.

More Information about Kava

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read

Test your knowledge

Computerized Tomography (CT)
In computerized tomography (CT), x-ray images of the body are taken from multiple angles and converted by a computer into images resembling 2- and 3-dimensional slices (cross-sections). People having a CT scan are asked to remove all jewelry and metal items such as zippers and belt buckles located near the body part being scanned. Why are patients asked to remove metal before having a CT scan?
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID