Herb & supplement monograph

Kava Drug Interactions, Uses, Effectiveness, Safety & More

Medically reviewed by ·Updated July 2026
What is this page for?

First and foremost: how Kava interacts with medications. The heart of this page is the interaction list — every drug Kava is known to interact with, and how serious each one is.

But these pages have grown well beyond that into a full monograph — what Kava is, what people use it for and how strong the evidence is, its safety and side effects, and answers to the questions we’re asked most — written and reviewed by the clinical staff at HelloPharmacist. It’s educational information from our licensed clinical databases, not medical advice, and we don’t sell or endorse products. Our editorial policy

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On this page

Kava Drug Interactions: The Bottom Line

From the HelloPharmacist Editorial Team · Updated July 2026

Based on the available evidence, Kava drug interactions carry a moderate overall risk of being clinically significant, and the risk rises considerably for anyone who takes sedating medicines or drinks alcohol. Hundreds of the listed interactions are rated major or moderate, and kava's best-documented effect, added sedation, is backed by human evidence.

Interactions deserving the most attention

The clearest concern is with CNS depressants such as sedatives, sleep medicines, and other calming drugs, where kava can add to drowsiness and slow reflexes. Combining kava with alcohol may increase both sedation and strain on the liver, since kava itself has been linked to over 100 reports of liver injury; similar caution applies to other medicines that can stress the liver. A human study also found kava slows one enzyme the body uses to clear certain medications, which could raise their levels.

What the rest of the list means

The long list of interactions does not mean every combination is harmful. Most entries are theoretical, based on lab research into enzymes and transporters that process medications. In fact, several of those predicted effects were later tested in people and produced no meaningful change, so many listed interactions may never matter in practice.

Check your medications against Kava

Based on HelloPharmacist’s Kava interaction data and reviewed under our editorial standards.

Interaction report

Drugs that interact with Kava

1167 medications have a known interaction with Kava, graded by severity. Select any drug for the full evidence-based detail.

248 major interactions. These combinations can be clinically significant — best avoided, or used only with close professional supervision. Always check with your pharmacist before combining them with Kava.

2,830 drugs
AcepromazineAtravet› Acetaminophen, Butalbital, Caffeine, CodeineEsgic with Codeine, Fioricet w/ Codeine› Acetaminophen, Butalbital, CodeineBancap w/ Codeine› Acetaminophen, Butalbital, Codeine PhosphatePhrenilin #3› Acetaminophen, Caffeine, Chlorpheniramine, Hydrocodone, PhenylephrineHycomine Compound› Acetaminophen, Caffeine, CodeineGesic C15, Gesic C30, Gesic C8, Lenoltec 1, Lenoltec 2, Lenoltec 3 +1 more› Acetaminophen, Caffeine, Codeine, SalicylamideCodalan No.1, Codalan No.2, Codalan No.3› Acetaminophen, Caffeine, DihydrocodeineDHC Plus, Panlor DC, Panlor SS› Acetaminophen, Chlorpheniramine, Codeine, PhenylephrineColrex› Acetaminophen, Chlorpheniramine, Phenylpropanolamine, OpiumHista-Derfule› Acetaminophen, Chlorzoxazone, CodeineAcetazone Forte C8, Parafon Forte C8› Acetaminophen, CodeineTylenol No.3, Tylenol w/ Codeine› Acetaminophen, Codeine, DoxylamineMersyndol› Acetaminophen, Codeine, MethocarbamolAcetaminophen, Codeine, Methocarbamol, Robaxacet 8› Acetaminophen, Dichloralantipyrine, IsomethepteneAmidrine, Midchlor, Migquin, Migratine› Acetaminophen, Dichloralphenazone, IsomethepteneMidrin› Acetaminophen, Dichlorophenazone, IsometheptaneIsocom› Acetaminophen, DiphenhydramineTylenol PM, Tylenol PM Ex Strength› Acetaminophen, Diphenhydramine, PseudoephedrineChildren's Tylenol Allergy, Cold Control, Contac Night Allergy Relief› Acetaminophen, HydrocodoneAnexsia, Anodynos DHC, Azdone, Co-Gesic, Doucet, Lorcet +9 more› Acetaminophen, MeperidineDemerol APAP› Acetaminophen, OxycodonePercocet, Roxicet, Tylox, Xartemis XR› Acetaminophen, PentazocineTalacen› Acetaminophen, PropoxypheneDarvocet-N 100, Darvocet-N 50, E-Lor, Wygesic› AcetazolamideAk-Zol, Diamox› AlfentanilAlfenta› AlprazolamNiravam, Xanax› Aluminum Hydroxide, Aspirin, Codeine Phosphate, Magnesium HydroxideAscriptin Codeine #2› AminoglutethimideCytadren› Aminophylline, Amobarbital, EphedrineAmesec›
Read The List Like a Pharmacist

What Severity, Likelihood & Evidence Mean

Severity — How Serious It Can Be

  • Major. Clinically significant; generally best avoided, or used only under direct professional supervision.
  • Moderate. May need monitoring, a dose adjustment, or separating the times you take each one.
  • Minor. Generally not clinically significant, but still worth noting and mentioning to your pharmacist.
  • No known interaction. Checked against our sources with nothing documented — not the same as proven safety.

Likelihood — How Well It’s Documented

  • Likely. Well-controlled human studies have demonstrated the likely existence of this interaction
  • Probable. Interaction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • Possible. Interaction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists
  • Unlikely. Interaction has been demonstrated in animal or in lab research but has been shown not to occur in humans.

Where This Data Comes From

  • Interaction records are evidence-graded and sourced from the Natural Medicines database (TRC Healthcare), the same reference used by pharmacists and hospitals.
  • Each drug listed above links to the full report for that exact Kava combination — clinical detail, likelihood, evidence level, and citations.
  • Content is reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.
The big picture

The kinds of drugs Kava affects

Every type of medication (drug category) Kava is known to interact with. Open any category for the detail — or search your exact drug in the checker above.

All 12 drug categories Kava interacts with
Cns DepressantsAlcohol (ethanol)Cytochrome P450 2c19 (cyp2c19) SubstratesCytochrome P450 2c9 (cyp2c9) SubstratesCytochrome P450 2e1 (cyp2e1) SubstratesHaloperidol (haldol)Hepatotoxic DrugsP-glycoprotein SubstratesRopinirole (requip)Cytochrome P450 1a2 (cyp1a2) SubstratesCytochrome P450 2d6 (cyp2d6) SubstratesCytochrome P450 3a4 (cyp3a4) Substrates
Cns Depressants

Combining kava with CNS depressants can have additive sedative effects.
Kava has CNS depressant effects. Concomitant use of kava with other CNS depressants can increase the risk of drowsiness and motor reflex depression. Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend that CNS depressants, including alcohol and benzodiazepines, not be used with kava.

Likelihood Probable Evidence A
Alcohol (Ethanol)

Combining kava with alcohol may increase the risk of sedation and/or hepatotoxicity.

Kava has CNS depressant effects. Concomitant use of kava with other CNS depressants can increase the risk of drowsiness and motor reflex depression. Additionally, kava has been associated with over 100 cases of hepatotoxicity. There is some concern that kava can adversely affect the liver, especially when used in combination with hepatotoxic drugs. Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend that alcohol not be used with kava.

Likelihood Possible Evidence A
Cytochrome P450 2C19 (Cyp2C19) Substrates

Theoretically, kava might increase levels of CYP2C19 substrates.
In vitro research shows that kava significantly inhibits CYP2C19 enzymes. This effect has not yet been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2C9 (Cyp2C9) Substrates

Theoretically, kava might increase levels of CYP2C9 substrates.
In vitro research shows that kava significantly inhibits CYP2C9 enzymes. This effect has not yet been reported in humans.

Likelihood Possible Evidence D
Cytochrome P450 2E1 (Cyp2E1) Substrates

Kava might increase levels of CYP2E1 substrates.
In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days inhibited the metabolism of CYP2E1 substrates.

Likelihood Probable Evidence B
Haloperidol (Haldol)

Combining kava and haloperidol might increase the risk of cardiovascular adverse effects and hypoxia.
Atrial flutter and hypoxia has been reported for a patient who received intramuscular injections of haloperidol and lorazepam after using kava orally. The side effects were attributed to kava-induced inhibition of CYP2D6, but might also have been related to additive adverse effects with the concomitant use of haloperidol, lorazepam, and kava.

Likelihood Possible Evidence D
Hepatotoxic Drugs

Theoretically, using kava with hepatotoxic drugs might increase the risk of liver damage.
Kava has been linked with over 100 cases of hepatotoxicity. Most cases occur with excessive and prolonged use. There is some concern that kava can adversely affect the liver, especially when used in combination with hepatotoxic drugs.

Likelihood Possible Evidence D
P-Glycoprotein Substrates

It is unclear if kava inhibits P-glycoprotein (P-gp); research is conflicting.
In vitro research shows that kava can inhibit P-gp efflux. However, a clinical study in healthy volunteers shows that taking kava standardized to provide 225 mg kavalactones daily for 14 days does not affect the pharmacokinetics of digoxin, a P-gp substrate. It is possible that the use of other P-gp substrates or higher doses of kava might still inhibit P-gp.

Likelihood Possible Evidence D
Ropinirole (Requip)

Taking kava with ropinirole might increase the risk for dopaminergic toxicity.
A case of visual hallucinations and paranoid delusions has been reported for a patient who used kava in combination with ropinirole. The adverse effects were attributed to kava-induced inhibition of CYP1A2, which may have reduced the metabolism of ropinirole, resulting in excessive dopaminergic stimulation.

Likelihood Possible Evidence D
Cytochrome P450 1A2 (Cyp1A2) Substrates

It is unclear if kava inhibits CYP1A2; research is conflicting.
Although in vitro research and a case report suggest that kava inhibits CYP1A2, more robust clinical evidence shows that kava has no effect on CYP1A2. In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days had no effect on CYP1A2 activity.

Likelihood Unlikely Evidence B
Cytochrome P450 2D6 (Cyp2D6) Substrates

It is unclear if kava inhibits CYP1A2; research is conflicting.
In vitro research shows that kava extract significantly inhibits CYP2D6. However, clinical research shows that kava does not affect the metabolism of CYP2D6 substrates in humans.

Likelihood Unlikely Evidence B
Cytochrome P450 3A4 (Cyp3A4) Substrates

It is unclear if kava inhibits CYP3AA; research is conflicting.
Although in vitro research suggests that kava inhibits CYP3A4, more robust clinical evidence shows that kava has no effect on CYP3A4. In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days had no effect on CYP3A4 activity.

Likelihood Unlikely Evidence B
Monograph

Kava: Uses, Safety & Side Effects

Medically reviewed by · Reviewed July 2026 ·
The bottom line

Kava is a Pacific Island plant traditionally used to promote relaxation and ease anxiety, and some studies suggest it may help mild anxiety. However, kava has been linked to rare but serious liver damage, so it should be used with caution, avoided by people with liver problems, and only used after talking with your pharmacist or doctor.

Kava
Scientific name
Piper methysticum
Family
Piperaceae
Part used
Roots and rhizomes
Common forms
Capsules, tablets, liquid extracts, tinctures, teas, and traditional water-based root drinks
People commonly use it for
  • Anxiety and stress
  • Restlessness
  • Trouble sleeping
  • Relaxation in social or cultural settings
  • Menopausal symptoms

Popular and traditional uses — not proof it works. See “Uses & effectiveness” below for the evidence.

Safety at a glance
OverallUse caution

Kava may help anxiety but has been linked to rare, serious liver injury and is banned or restricted in some countries.

PregnancyBest avoided

Kava is not considered safe during pregnancy and should be avoided.

BreastfeedingPossibly Unsafe

When used orally. There is concern that the toxic pyrone constituents of kava can pass into breast milk; avoid using.

Read the full breastfeeding detail

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center). Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Jump to a section

Overview

Kava (Piper methysticum) is a tropical plant native to the islands of the South Pacific, including Fiji, Vanuatu, Tonga, and Samoa. For hundreds of years, Pacific Island cultures have prepared a drink from the plant's roots and used it during social gatherings, ceremonies, and to help people relax.

The roots contain active compounds called kavalactones, which are thought to be responsible for kava's calming and relaxing effects. Today, kava is sold around the world as a dietary supplement in the form of capsules, liquid extracts, teas, and traditional root preparations. People most often take it hoping to reduce anxiety, ease stress, and unwind.

How it works

Kava's effects are believed to come from a group of compounds called kavalactones. Laboratory and animal research suggests these compounds may act on the brain in ways similar to some calming medications, possibly by affecting GABA, a chemical messenger that helps quiet nerve activity.

Kavalactones may also influence other brain pathways involved in mood, muscle tension, and the body's response to stress. It is important to know that much of this understanding comes from laboratory and animal studies, and scientists do not yet fully understand exactly how kava works in people.

Effectiveness

Does Kava work?

Here’s what the research actually shows for each use — graded by Natural Medicines and reviewed by .

Evidence overview · 10 uses evaluated
1 Leans ineffective 9 Insufficient evidence
How to read these evidence grades

Natural Medicines’ 7-point scale. We show each rating’s label word-for-word.

1EffectiveStrong, consistent evidence it works.
2Likely EffectiveGood evidence, though not yet conclusive.
3Possibly EffectiveSome evidence suggests a benefit.
4Possibly IneffectiveSome evidence it may not help.
5Likely IneffectiveFairly strong evidence it doesn’t help.
6IneffectiveStrong evidence it doesn’t work.
7Insufficient Reliable Evidence to RateToo little research to say either way.
Possibly Ineffective Generalized anxiety disorder (GAD)
Rating & evidence shown verbatim from Natural Medicines

Oral kava doesn't seem to be effective for treating GAD.

Also studied for 9 conditions — evidence insufficient to rate
Insufficient Reliable Evidence To Rate Benzodiazepine withdrawal
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral kava is beneficial for reducing benzodiazepine withdrawal symptoms.

Insufficient Reliable Evidence To Rate Cancer
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral kava is beneficial in patients with cancer.

Insufficient Reliable Evidence To Rate Epilepsy
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral kava for epilepsy, there is insufficient reliable information about the clinical effects of kava for this condition.

Insufficient Reliable Evidence To Rate Insomnia
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral kava is beneficial in patients with insomnia.

Insufficient Reliable Evidence To Rate Menopausal symptoms
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral kava is beneficial for menopausal symptoms.

Insufficient Reliable Evidence To Rate Myalgia
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral kava for myalgia, there is insufficient reliable information about the clinical effects of kava for this condition.

Insufficient Reliable Evidence To Rate Premenstrual syndrome (PMS)
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral kava for PMS, there is insufficient reliable information about the clinical effects of kava for this condition.

Insufficient Reliable Evidence To Rate Sexual arousal
Rating & evidence shown verbatim from Natural Medicines

Although there is interest in using oral kava for sexual arousal, there is insufficient reliable information about the clinical effects of kava for this condition.

Insufficient Reliable Evidence To Rate Stress
Rating & evidence shown verbatim from Natural Medicines

It is unclear if oral kava reduces reactivity to experimental stress.

Source & disclaimer. Effectiveness ratings and evidence summaries are provided by Natural Medicines (Therapeutic Research Center) and shown as licensed. Where Natural Medicines hasn’t rated a use, HelloPharmacist’s pharmacists may add their own reviewed rating and evidence (each such entry is labeled). This is educational information, not medical advice — talk with your pharmacist or doctor before starting, stopping, or changing a supplement.

Safety & precautions

The biggest safety concern with kava is the possibility of liver damage. Reports have linked kava to serious liver problems, including liver failure that in rare cases required a transplant. Because of this, some countries (such as the United Kingdom) have banned or restricted kava, and regulators in several countries have issued warnings.

People who should avoid kava or use extra caution include those with liver disease, those who drink alcohol regularly, and anyone taking medications that can affect the liver. You should stop kava and contact your doctor right away if you notice signs of liver trouble, such as yellowing of the skin or eyes, dark urine, unusual tiredness, nausea, or stomach pain.

Pregnancy and breastfeeding: Kava should be avoided during pregnancy and while breastfeeding. There is not enough safety information, and the compounds may pass to the baby. Always speak with your pharmacist or doctor before using kava, especially if you have a health condition or take other medicines.

Side effects

Common side effects of kava can include drowsiness, headache, dizziness, and stomach upset. Kava can cause sleepiness and may slow reactions, so it may not be safe to drive or operate machinery after taking it.

Long-term or heavy use has been linked to a dry, scaly skin condition known as kava dermopathy, which usually improves after stopping kava. The most serious concern is rare but potentially severe liver injury. Stop taking kava and seek medical care if you develop symptoms that could signal liver problems.

Kava: Reported Adverse Effects

Documented safety reports on Kava from the evidence-graded Natural Medicines (TRC Healthcare) database, shown word-for-word from the licensed record.

Orally, kava seems to be well tolerated.

Most Common Adverse Effects:

Orally: Drowsiness, dry mouth, dizziness, gastrointestinal upset, headache, memory problems, tremor.

Serious Adverse Effects (Rare):

Orally: There have been over 100 reported cases of hepatotoxicity and a few reported cases of rhabdomyolysis.

Reports by condition
Anxiety Hepatic

Since the early 2000's, hepatotoxicity has been a particular concern with kava. Worldwide, there have been at least 100 reported cases of hepatotoxicity following use of kava products. However, some experts question the clinical validity of several of these cases. Some cases were reported multiple times and in some cases it was unlikely that kava was the causative agent.

In susceptible patients, symptoms can show up after as little as 3-4 weeks of kava use. Symptoms include yellowed skin (jaundice), fatigue, and dark urine. Liver function tests can be elevated after 3-8 weeks of use, possibly followed by hepatomegaly and onset of encephalopathy. Kava has also been reported to exacerbate hepatitis in patients with a history of recurrent hepatitis. However, in many cases, symptoms seem to resolve spontaneously, and liver function tests usually normalize within eight weeks.

Liver toxicity is more frequently associated with prolonged use of very high doses. But there is some concern that even short-term use of kava in typical doses might cause acute hepatitis in some patients, including severe hepatocellular necrosis. The use of kava for as little as 1-3 months has resulted in need for liver transplant and death, although these events are rare.

There is some speculation that the type of extraction method could be responsible for these rare cases of hepatotoxicity. The "Pacific kava paradox" holds that while the alcohol and acetone extracts of kava used for commercial products cause liver toxicity, the traditional kava rhizome preparation mixed with water might not be toxic. However, a more recent analysis reports cases of hepatotoxicity from the aqueous kava extract and suggests that kava's hepatotoxic effects may be due to contaminants such as mold. Other suggested causes of hepatotoxicity include quality of the kava plant, concomitant medications, large doses and prolonged use, and toxic constituents and metabolites of kava.

Some commercial kava extracts contain parts of the stems and other aerial parts in addition to the rhizome, and it has been suggested that a constituent called pipermethysine, which is only found in these aerial parts, might be partly responsible for hepatotoxicity. Other constituents of kava which might contribute to hepatotoxicity are kavalactones, which are metabolized by cytochrome P450 (CYP450) enzymes in the liver. Reactive metabolites are produced which conjugate with glutathione, and might deplete glutathione in a similar manner to acetaminophen. Increased levels of gamma-glutamyl transferase, involved in the production of glutathione, have been reported in chronic kava users. One of the enzymes involved in production of reactive metabolites from kavalactones is cytochrome P450 2E1 (CYP2E1), which is induced by chronic alcohol intake. Alcohol may also compete for other enzymes which clear kavalactone metabolites from the body. This might explain the observation that alcohol ingestion seems to increase the risk of hepatotoxicity with kava.

There is also speculation that "poor metabolizers" or those patients with deficiency in the cytochrome P450 2D6 (CYP2D6) isoenzyme, which occurs in up to 10% of people of European descent, may be at increased risk for hepatotoxic effects from kava. This deficiency has not been found in Pacific Islanders. However, this theory has not been confirmed.

Due to the concerns regarding the potential hepatotoxicity of kava, kava supplements were withdrawn from European and Canadian markets in 2002. However, many of the market withdrawals of kava have been lifted after re-evaluation of kava suggested that the risk of hepatotoxicity was minimal. Still, clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend exercising caution when using kava in patients with preexisting liver issues. Until more is known, tell patients to use kava cautiously and recommend liver function tests for routine users or those with underlying liver disease.

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Cluster headache Neurologic/CNS

Orally, kava may cause headache, dizziness, and drowsiness. It might also cause extrapyramidal side effects such as involuntary oral and lingual reflexes, twisting movements of the head and trunk, tremors, and other parkinsonian-like symptoms possibly due to dopamine antagonism. In one clinical trial, patients taking a kava supplement providing 120 mg of kavalactones twice daily for 16 weeks had a 3.2-fold greater risk of experiencing tremors when compared with patients taking placebo. Theoretically, kava may worsen symptoms in patients with Parkinson disease or precipitate Parkinson-like symptoms in certain patients. Unlike benzodiazepines, kava is not thought to be associated with impaired cognitive function. However, one clinical trial shows that taking a kava supplement providing 120 mg of kavalactones twice daily for 16 weeks increases the risk for memory impairment by 55% when compared with placebo.

Orally, kava may reduce alertness and impair motor coordination in a dose-dependent manner. Some preliminary reports have noted a decline in accuracy of visual attention and slower reaction times after kava ingestion, particularly at higher doses and in combination with alcohol. Population research has also found that ingesting large amounts of kava tea (typically 50 times higher than what is used medicinally in the US) within a 12-hour period before driving increases the odds of being involved in a serious motor vehicle crash resulting in death or serious injury by almost 5-fold when compared to not drinking kava tea. Use of normal doses of kava may also affect the ability to drive or operate machinery, and driving under the influence (DUI) citations have been issued to individuals observed driving erratically after drinking large amounts of kava tea. However, in computer-based driving simulator tests, there are no reported adverse effects of kava on performance. Additionally, other research shows that consuming over 4400 mg of kavalactones over a 6-hour kava session does not seem to impair alertness or attention when compared with non-kava drinkers. Similar research using a specific psychometric tool (Brain Gauge) shows that consuming approximately 3680 mg of kavalactones in a 6-hour kava session seems to impair temporal order judgment, which is associated with the brain's ability to track the order of events, when compared with non-kava drinkers. However, it does not seem to impact cognitive domains related to focus, accuracy, timing perception, plasticity, or fatigue when compared with non-kava drinkers.

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  12. Sarris J, Byrne GJ, Bousman CA, et al. Kava for generalised anxiety disorder: A 16-week double-blind, randomised, placebo-controlled study. Aust N Z J Psychiatry. 2020 Mar;54(3):288-297.
  13. Heinze HJ, Munthe TF, Steitz J, Matzke M. Pharmacopsychological effects of oxazepam and kava-extract in a visual search paradigm assessed with event-related potentials. Pharmacopsychiatry 1994;27:224-30.
  14. Munte TF, Heinze HJ, Matzke M, Steitz J. Effects of oxazepam and an extract of kava roots (Piper methysticum) on event-related potentials in a word recognition task. Neuropsychobiology 1993;27:46-53.
  15. Gessner B and Cnota P. Extract of the kava-kava rhizome in comparison with diazepam and placebo. Z Phytother 1994;15(1):30-37.
  16. Johnson D, Frauendorf A, Stecker K, and et al. Neurophysiological active profile and tolerance of kava extract WS 1490, A pilot study with randomized evaluation. TW Neurolgie Psychiatrie 1991;5(6):349-354.
  17. Wainiqolo I, Kool B, Nosa V, Ameratunga S. Is driving under the influence of kava associated with motor vehicle crashes? A systematic review of the epidemiological literature. Aust N Z J Public Health 2015;39(5):495-9.
  18. Wainiqolo I, Kafoa B, Kool B, et al. Driving following kava use and road traffic injuries: a population-based case-control study in Fiji (TRIP 14). PLoS One 2016;11(3):e0149719.
  19. Swensen JN. Man convicted of driving under the influence of kava. Salt Lake City, UT: Deseret News, 1996.
  20. Aporosa AS, Atkins M, Brunton R. Kava drinking in traditional settings: towards understanding effects on cognitive function. Hum Psychopharmacol. 2020;35(2):e2725.
  21. Aporosa S', Ballard H, Pandey R, McCarthy MJ. The impact of traditional kava (Piper methysticum) use on cognition: Implications for driver fitness. J Ethnopharmacol 2022;291:115080.
Dermatitis Dermatologic

Orally, kava can cause allergic skin reactions, including sebotropic eruptions, delayed-type hypersensitivity, or urticarial eruption. In one case of kava-associated urticarial eruption, biopsy revealed neutrophilic sebaceous glands with lymphocytic infiltrate. Chronic use of high doses of kava has also been associated with kava dermopathy, which consists of reddened eyes; dry, scaly, flaky skin; and temporary yellow discoloration of the skin, hair, and nails. This pellagra-like syndrome is unresponsive to niacinamide treatment. The cause is unknown, but may relate to interference with cholesterol metabolism. Kava's adverse effects on liver function might also contribute to kava dermopathy. Kava dermopathy usually occurs within three months to one year of regular kava use, and resolves when the kava dose is decreased or discontinued. Kava dose should be decreased or discontinued if kava dermopathy occurs. In addition to kava cessation, oral or topical corticosteroids have been described as treatment options in some cases of kava associated dermatitis.

  1. Wheatley D. Stress-induced insomnia treated with kava and valerian: singly and in combination. Hum Psychopharmacol 2001;16:353-6.
  2. Schmidt P, Boehncke WH. Delayed-type hypersensitivity reaction to kava-kava extract. Contact Dermatitis 2000;42:363-4.
  3. Huynh JC, Asgari MM, Moore MM. Sebotropic eruption associated with use of oral kava kava supplement. Clin Exp Dermatol 2014;39(7):816-8.
  4. Grace, R. Kava-induced urticaria. J Am Acad Dermatol 2005;53(5):906.
  5. Jappe, U., Franke, I., Reinhold, D., and Gollnick, H. P. Sebotropic drug reaction resulting from kava-kava extract therapy: a new entity? J Am Acad Dermatol. 1998;38(1):104-106.
  6. Siegers CP, Honold E, Krall B, and et al. Results of the drug monitoring L 1090 with Laitan capsules. Arztl Forsch 1992;39:7-11.
  7. du Plessis Nisbet J, Xie D, Thompson R, Wark K, Lamrock E, Scurry J. Kava-induced dermatitis: A detailed histopathological analysis. Australas J Dermatol 2024.
  8. Norton SA, Ruze P. Kava dermopathy. J Am Acad Dermatol 1994;31:89-97.
  9. Pizzorno JE, Murray MT, eds. Textbook of Natural Medicine. 2nd ed. Edinburgh:Churchill Livingstone, 1999.
  10. Singh YN. Kava: an overview. J Ethnopharmacol 1992;37:13-45.
  11. Wooltorton E. Herbal kava: reports of liver toxicity. CMAJ 2002;166:777.
  12. Hannam S, Murray M, Romani L, Tuicakau M, J Whitfeld M. Kava dermopathy in Fiji: an acquired ichthyosis? Int J Dermatol 2014;53(12):1490-4.
  13. Keller F and Klohs M. A review of the chemistry and pharmacology of the constituents of Piper methysticum. Lloydia 1963;26:1-15.
  14. Ruze P. Kava-induced dermopathy: a niacin deficiency? Lancet 1990;335:1442-5.
Dry mouth Gastrointestinal

Orally, kava may cause gastrointestinal upset, nausea, or dry mouth.

  1. Pittler MH, Ernst E. Efficacy of kava extract for treating anxiety: systematic review and meta-analysis. J Clin Psychopharmacol 2000;20:84-9.
  2. Volz HP, Kieser M. Kava-kava extract WS 1490 versus placebo in anxiety disorders--a randomized placebo-controlled 25-week outpatient trial. Pharmacopsychiatry 1997;30:1-5.
  3. Wheatley D. Stress-induced insomnia treated with kava and valerian: singly and in combination. Hum Psychopharmacol 2001;16:353-6.
  4. Schmidt P, Boehncke WH. Delayed-type hypersensitivity reaction to kava-kava extract. Contact Dermatitis 2000;42:363-4.
  5. Sarris J, Kavanagh DJ, Byrne G, et al. The Kava Anxiety Depression Spectrum Study (KADSS): a randomized, placebo-controlled crossover trial using an aqueous extract of Piper methysticum. Psychopharmacology 2009;205:399-407.
  6. Scherer, J. Kava-kava extract in anxiety disorders: an outpatient observational study. Adv.Ther. 1998;15(4):261-269.
  7. Siegers CP, Honold E, Krall B, and et al. Results of the drug monitoring L 1090 with Laitan capsules. Arztl Forsch 1992;39:7-11.
Hypertension Cardiovascular

Long-term use of very large amounts of kava, especially in high doses (400 mg kava pyrones daily), has been associated with overall poor health including symptoms of low body weight, reduced protein levels, puffy face, hematuria, increased red blood cell volume, decreased platelets and lymphocytes, and possibly pulmonary hypertension. Tachycardia and electrocardiogram (ECG) abnormalities (tall P waves) have been reported in heavy kava users.

  1. Mathews JD, Riley MD, Fejo L, et al. Effects of heavy usage of kava on physical health: Summary of a pilot survey in an aboriginal community. Med J Aust 1988;148:548-55.
Hypertension Pulmonary/Respiratory

Orally, kava may cause shortness of breath, possibly due to pulmonary hypertension.

  1. Mathews JD, Riley MD, Fejo L, et al. Effects of heavy usage of kava on physical health: Summary of a pilot survey in an aboriginal community. Med J Aust 1988;148:548-55.
Muscle breakdown Musculoskeletal

Kava has been linked with reports of rhabdomyolysis. A 34-year-old man who consumed kava tea several times a week developed rhabdomyolysis with a peak creatine kinase level of 32,500 units/liter. However, there is speculation that this might have been due to product impurities rather than kava itself. Another case report describes rhabdomyolysis with myoglobinuria and a creatine kinase level of 100,500 units/liter in a 29-year-old man who had taken kava in combination with guarana and ginkgo biloba.

Cases of ataxia and tremors have been reported in patients taking single doses of kava powder 205 grams.

  1. Bodkin R, Schneider S, Rekkerth D, et al. Rhabdomyolysis associated with kava ingestion. Am J Emerg Med 2012;30:635.el-3.
  2. Donadio V, Bonsi P, Zele I, et al. Myoglobinuria after ingestion of extracts of guarana, Ginkgo biloba and kava. Ginkgo biloba and kava. Neurol Sci 2000;21:124.
  3. Cairney S, Maruff P, Clough AR, et al. Saccade and cognitive impairment associated with kava intoxication. Hum Psychopharmacol 2003;18:525-33.
Substance use disorder Immunologic

Sjögren syndrome has been associated with an herbal supplement containing kava, echinacea, and St. John's wort. Echinacea may have been the primary cause, because Sjögren syndrome is an autoimmune disorder. The role of kava in this syndrome is unclear.

  1. Logan JL, Ahmed J. Critical hypokalemic renal tubular acidosis due to Sjogren's syndrome: association with the purported immune stimulant echinacea. Clin Rheumatol 2003;22:158-9.
Urinary retention Renal

Orally, kava may cause acute urinary retention.

  1. Leung, N. Acute urinary retention secondary to kava ingestion. Emerg Med Australas 2004;16(1):94.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

Adverse-effects data: Natural Medicines, Therapeutic Research Center

Dosing

There is no single established or standardized dose for kava, and products vary widely in how much kavalactone they contain. Because of this and the risk of liver harm, it is best not to guess at a dose on your own.

If you and your healthcare provider decide kava is appropriate, follow the directions on the product label and use the lowest effective amount for the shortest time. Many experts advise limiting how long you use kava. Always check with your pharmacist or doctor before starting, and let them know about any other medicines or supplements you take.

Pregnancy & Breastfeeding

Kava & Breastfeeding

Possibly Unsafe

When used orally. There is concern that the toxic pyrone constituents of kava can pass into breast milk; avoid using.

  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.

© 2026 Therapeutic Research Center

Pregnancy & lactation ratings: Natural Medicines, Therapeutic Research Center

References & further reading

The 71 references that drive our Kava monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Strahl S, Ehret V, Dahm HH, Maier KP. [Necrotizing hepatitis after taking herbal medication]. Dtsch Med Wochenschr 1998;123:1410-4.
  3. Spillane PK, et al. Neurological manifestations of kava intoxication. Med J Aust 1997;167:172-3. PubMed
  4. Swensen JN. Man convicted of driving under the influence of kava. Salt Lake City, UT: Deseret News, 1996.
  5. Pittler MH, Ernst E. Efficacy of kava extract for treating anxiety: systematic review and meta-analysis. J Clin Psychopharmacol 2000;20:84-9. PubMed
  6. Volz HP, Kieser M. Kava-kava extract WS 1490 versus placebo in anxiety disorders--a randomized placebo-controlled 25-week outpatient trial. Pharmacopsychiatry 1997;30:1-5. PubMed
  7. Heinze HJ, Munthe TF, Steitz J, Matzke M. Pharmacopsychological effects of oxazepam and kava-extract in a visual search paradigm assessed with event-related potentials. Pharmacopsychiatry 1994;27:224-30. PubMed
  8. Munte TF, Heinze HJ, Matzke M, Steitz J. Effects of oxazepam and an extract of kava roots (Piper methysticum) on event-related potentials in a word recognition task. Neuropsychobiology 1993;27:46-53.
  9. Wheatley D. Stress-induced insomnia treated with kava and valerian: singly and in combination. Hum Psychopharmacol 2001;16:353-6. PubMed
  10. Schelosky L, Raffaup C, Jendroska K, Poewe W. Kava and dopamine antagonism. J Neurol Neurosurg Psychiatry 1995;58:639-40. PubMed
  11. Norton SA, Ruze P. Kava dermopathy. J Am Acad Dermatol 1994;31:89-97.
  12. Pizzorno JE, Murray MT, eds. Textbook of Natural Medicine. 2nd ed. Edinburgh:Churchill Livingstone, 1999.
  13. Mathews JD, Riley MD, Fejo L, et al. Effects of heavy usage of kava on physical health: Summary of a pilot survey in an aboriginal community. Med J Aust 1988;148:548-55.
  14. Escher M, Desmeules J, Giostra E, Mentha G. Hepatitis associated with Kava, a herbal remedy for anxiety. BMJ 2001;322:139.
  15. Russmann S, Lauterburg BH, Helbling A. Kava hepatotoxicity [letter]. Ann Intern Med 2001;135:68-9.
Keep reading

This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

Brand directory

Brands that make products with Kava

106 brands in our database make a supplement containing Kava.

Product directory

Supplement products with Kava

410 products in our database contain Kava. Open any to see its full ingredient list and every drug interaction we check.

Blackberry + Yuzu Flavor by Psychedelic Water Liquid 12 Fluid Ounce(s) · 355 Milliliter(s) View ingredients & interactions Bladder Control by Crystal Star Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Bladder Strength by Crystal Star Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Bladder Support by Crystal Star Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Bliss + by Herbal Goodness Liquid 12 Ounce(s) · 354 Milliliter(s) View ingredients & interactions Body Comfort by Meehan Formulations Capsule 120 Capsule(s) View ingredients & interactions Body Comfort Formula by BioFactor Capsule 120 Capsule(s) View ingredients & interactions Botanicalm by Ortho Molecular Products Capsule 60 Capsule(s) View ingredients & interactions California Poppy and Kava Kava by Hawaii Pharm Liquid 4 Fluid Ounce(s) · 120 mL View ingredients & interactions California Poppy and Kava Kava by Herbal Terra Liquid 4 Fluid Ounce(s) · 120 mL View ingredients & interactions California Poppy and Kava Kava by Herbal Terra Liquid 4 Fluid Ounce(s) · 120 mL View ingredients & interactions California Poppy and Kava Kava by Herbal Terra Liquid 2 Fluid Ounce(s) · 60 mL View ingredients & interactions California Poppy and Kava Kava Alcohol Free by Herbal Terra Liquid 2 Fluid Ounce(s) · 60 mL View ingredients & interactions California Poppy and Kava Kava Non-Alcohol by Hawaii Pharm Liquid 4 Fluid Ounce(s) · 120 mL View ingredients & interactions Calm Surfer by Remedys Nutrition Capsule 60 Vcap(s) View ingredients & interactions Calm Surfer by Remedys Nutrition Liquid 2 fl. Oz. · 60 mL View ingredients & interactions Calm Surfer 1000 mg by Remedys Nutrition Capsule 60 Vcap(s) View ingredients & interactions Calm Synergy Kava Root Capsules 400 mg + CBD 30 mg by CBDistillery Capsule 30 Capsule(s) View ingredients & interactions Carefree Chocolate Mellow Truffle Mint Flavor by The Functional Chocolate Company Bar 1.75 Ounce(s) · 50 Gram(s) View ingredients & interactions Core-21 by 1st Phorm Capsule 60 Capsule(s) View ingredients & interactions Core-21 by 1st Phorm Capsule 60 Capsule(s) View ingredients & interactions Cough & Smoking Ease by Remedys Nutrition Capsule 60 Vcap(s) View ingredients & interactions Crave Eze by Crystal Star Capsule 60 Vegetarian Capsule(s) View ingredients & interactions Daily Calm Tonic Citrus by Vitanica Tasty Tonics Liquid 4 Fluid Ounce(s) · 118 mL View ingredients & interactions
Pharmacist Counseling Corner

Kava: Common Questions

What is Kava used for, and does it work?
People use Kava for a range of reasons, but according to the Natural Medicines database the current clinical evidence is insufficient to confirm it works for the specific conditions it has been studied for. See the graded list on this page, and talk to your pharmacist or doctor before relying on it for any condition.
Does Kava interact with prescription medications?
Yes. We list 1167 medications with a known interaction with Kava, including 248 rated major. Use the checker above to see how Kava interacts with a specific drug.
How are Kava interactions rated?
Each interaction is graded major, moderate, or minor based on how clinically significant it is and the strength of the evidence behind it. Major interactions are the most serious and are best avoided, or used only under close professional supervision.
Is it safe to take Kava with my medications?
It depends on the specific medication. Some combinations are fine, while others call for monitoring, timing changes, or should be avoided. Check your exact drug above and confirm with your pharmacist or doctor before starting, stopping, or changing anything.
Where does this Kava interaction information come from?
Our interaction data is built on the Natural Medicines database — an evidence-graded reference for vitamins, herbs, and supplements — and is reviewed by licensed HelloPharmacist pharmacists, who may add clinical context.
What is Kava used for?
Kava is most often used to help with anxiety and stress, and some people use it for restlessness or trouble sleeping. Some studies suggest it may help mild anxiety, but the evidence is not strong enough to call it a proven treatment.
Is Kava safe?
Kava has been linked to rare but serious liver damage, and it is banned or restricted in some countries. It should be avoided by people with liver problems and used only with caution and medical guidance.
Can I take Kava during pregnancy or while breastfeeding?
No. Kava should be avoided during pregnancy and breastfeeding because there is not enough safety information and the compounds may reach the baby.
Does Kava make you sleepy or impair driving?
Kava can cause drowsiness, dizziness, and slowed reactions, so it may not be safe to drive or operate machinery after taking it.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

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Products that contain Kava

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