Kava

Pronunciation: pronunciation varies by local usage.

Generic name: kava (Piper methysticum)
Drug class: Herbal dietary supplement (Piper methysticum, pepper family)
Form: Sources describe both traditional water-prepared beverages and commercial extracts.
Route: Oral (beverage, capsules, tablets, extracts)
Legal status: In the United States: available as a dietary supplement, not banned. Since 2002, kava was banned from sale or consumption in several countries (including United Kingdom, Germany, Switzerland, France, and Canada) due to liver toxicity concerns — current-day status in those countries was not independently rechecked in the sources reviewed for this page.

Availability and supply rules vary by country

Trade names by country:

What kava (Piper methysticum) is and how it works

Kava is an herbal dietary supplement made from the root of the kava plant (Piper methysticum), native to the South Pacific. Marketed in the United States primarily for anxiety, it is also sold at kava bars. Due to liver toxicity concerns, kava has been banned in several countries. (1) (2)

Kava products are not standardized. Evidence for anxiety requires several weeks of use, and it has not been shown effective specifically for generalized anxiety disorder. Serious liver injury has occurred with both traditional water-prepared and commercial solvent-extracted products. People with liver conditions, those taking sedatives or alcohol, and pregnant or breastfeeding individuals should avoid it.

Mechanism of action: how kava (Piper methysticum) works

The active constituents are described as pyrone compounds. (1) (2)

What kava (Piper methysticum) is used for

Anxiety

Kava may have mild anxiolytic effects, but the evidence is limited and typically requires several weeks of use. It has not been demonstrated effective for generalized anxiety disorder specifically. Other promoted uses lack sufficient scientific evidence. (1)

Before taking kava (Piper methysticum)

Do not take / not appropriate for

Tell your healthcare provider if you have liver disease, elevated liver enzymes, or a prior liver reaction to kava, before using kava — they can advise whether it is appropriate for you. (all products) (1) (2)
NCCIH advises that kava should not be used together with alcohol or sedative medications such as benzodiazepines. (all products) (1)
NCCIH advises avoiding kava during pregnancy and while breastfeeding. (all products) (1)

Tell your clinician about

Any history of liver problems, including elevated liver enzymes or jaundice.
All current medications, especially sedatives or benzodiazepines, and alcohol use.
Alcohol consumption patterns.
Tell your healthcare provider about any symptom that concerns you, particularly anything unusual affecting digestion, energy, urine, or skin/eye color.
Any skin changes, such as dry, scaly patches, redness of eyes, or yellow discoloration of skin, hair, or nails.
Pregnancy, plans for pregnancy, or breastfeeding.

(1) (2)

How to take kava (Piper methysticum)

Kava is taken orally as a beverage (from powdered root), capsule, tablet, or liquid extract. The quality and concentration of active compounds vary widely among products.
Discuss appropriate use with a healthcare provider.
Liver injury has occurred with both traditional water-prepared beverages and commercial solvent extracts; no preparation method is established as safe.
NCCIH advises talking with a healthcare provider before combining kava with alcohol, sedatives, or any other medicine.

(1) (2)

Procedures and treatment changes

Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (1) (2)

Missed dose

No standard missed-dose instructions exist. Consult your healthcare provider for guidance.

Overdose

If overdose is suspected, contact a poison control center or emergency services promptly. (2)

Side effects

Kava can cause digestive upset, headache, dizziness, and, with long-term high-dose use, a skin condition known as kava dermopathy. The most serious risk is liver injury, which can be severe or fatal.

Digestive upset

What to notice: Nausea, stomach discomfort.

What to do: If persistent or severe, consult a healthcare provider for assessment. (1)

Headache

What to notice: Mild to moderate headache.

What to do: Report persistent or troublesome headaches to a healthcare provider. (1)

Dizziness

What to notice: Feeling lightheaded or unsteady.

What to do: Use caution with activities requiring alertness; consult a provider if severe or frequent. (1)

Kava dermopathy

What to notice: Dry, scaly, flaky skin; reddened eyes; temporary yellow discoloration of skin, hair, and nails after long-term high-dose use.

What to do: Consult a healthcare provider about this symptom and what it means for your kava use. (1)

Liver injury

What to notice: Reported liver injury has ranged from transient liver-enzyme elevations to fulminant liver failure and death.

What to do: Seek immediate medical attention for anything you are concerned about. (2)

Serious warnings

Liver toxicity — emergency

Symptoms: Rare cases of liver injury have been serious or fatal, ranging up to fulminant liver failure.

Action: Seek emergency medical attention immediately for anything you are concerned about. (2)

Interactions

Medicine or test	Effect	Action
Alcohol and sedatives (e.g., benzodiazepines)	NCCIH advises kava should not be used together with these.	Tell your healthcare provider about all medicines and alcohol use before combining with kava. (1)
Any other medicine	Not established from the sources reviewed: a specific interaction list beyond alcohol and sedatives was not established in the sources reviewed for this page.	NCCIH advises talking with a healthcare provider before using kava if you take any medicine. (1)

Pregnancy, breastfeeding, kidney/liver function, age

Pregnancy and breastfeeding

Kava should be avoided due to potential harm from pyrone constituents. Insufficient safety data exist. (1)

Liver disease

Kava has been associated with rare but potentially serious or fatal liver injury. If you have liver disease or a prior liver reaction to kava, discuss this with a healthcare provider before use so they can advise whether kava is appropriate for you. (2)

Monitoring

Before starting

Discuss potential benefits and risks, including hepatotoxicity and dermopathy, with a healthcare provider before use.

During treatment

If you notice symptoms you are concerned about, or skin changes, contact your healthcare provider, who will assess and advise on whether kava should be continued.

(2)

Storage

Storage instructions were not reviewed in the current research. Follow the product label and consult a pharmacist.

Professional information

Clinician-facing context only. Kava is not an FDA-approved drug; it is a dietary supplement. Dosing, standardization, and safety are not regulated as drugs. Always consult the most current product-specific information and local regulatory status.

United States (dietary supplement)

Indication: Anxiety (1) (2)

United Kingdom, Germany, Switzerland, France, Canada (historical, since 2002)

Indication: All

Dose summary: Per the reviewed LiverTox source, kava was banned from sale/consumption in these countries since 2002. Current-day status was not independently rechecked in the sources reviewed for this page.

Renal context: Not applicable. (2)

Mechanism of action

Hepatic guidance

Kava has been associated with rare but potentially serious or fatal hepatotoxicity, ranging up to fulminant liver failure and death. The exact cause is unclear; proposed contributing factors include undesirable cultivars, inappropriate plant parts, alcohol co-use, contamination/adulteration, individual genetic susceptibility, and high-dose or prolonged use — none of these is established as the definitive mechanism.

Frequently asked questions

Is kava safe for long-term use?

High-dose or prolonged use is described as a possible contributing factor to liver injury, and long-term high-dose use can cause kava dermopathy. Discuss long-term use with a healthcare provider. (1) (2)

Can kava be taken with other anti-anxiety medications?

NCCIH advises that kava should not be combined with benzodiazepines, alcohol, or other sedative medications. For other medications, consult a healthcare provider before using kava. (1)

Why is kava banned in some countries but not the USA?

Due to reports of serious liver injury, several countries (UK, Germany, Switzerland, France, Canada) banned kava since 2002. Kava has not been banned in the United States and remains available as a dietary supplement. (2)

How quickly does kava work for anxiety?

Studies suggest that kava may require several weeks of use to show an effect. It has not been shown to be effective for acute anxiety or generalized anxiety disorder specifically. (1)

What is the mechanism of action of kava (Piper methysticum)?