Is kava safe?
Straight answers.

Around 2000, doctors in Europe started reporting liver damage in people taking kava pills and extracts. LiverTox, the NIH's reference on drug-induced liver injury, lists kava as a known cause. It's rare, estimated at under one case per million daily doses, and usually shows up 2 to 24 weeks after someone starts. Some cases ended in a liver transplant or death.3

In 2002 the FDA warned that kava supplements may be linked to severe liver injury, citing more than 25 reports from other countries, four transplants abroad and one in the US.4 Germany pulled kava medicines the same year.5

Most cases involved concentrated extracts made with acetone or ethanol and sold as pills. Not all of them: in one clinical review, 3 of 14 cases involved water-based extracts,11 and the NIH says some cases involved kava drinks made with water.2 FAO and WHO, reviewing the traditional drink, found only three published cases tied to it.1 Nobody knows for sure what causes the injury. The suspects include the wrong varieties, the wrong parts of the plant, poor-quality root, and taking kava with alcohol or other drugs.23

In trials of a water-based kava extract, a 6-week study found no difference from placebo on liver tests,16 while a 16-week study found abnormal liver tests more often in the kava group, though no one met the criteria for liver injury.17 Regular heavy drinkers often show a raised liver enzyme (GGT) that has gone back to normal within weeks of stopping.115

What happened in Germany

1. 2002Germany's drug regulator, BfArM, withdraws kava medicines over the liver reports.5
2. 2007It revokes their licenses.5
3. 2014The Administrative Court of Cologne strikes down the revocation.6
4. 2015The higher court agrees, finding liver events rare but potentially life-threatening.78
5. 2019BfArM revokes the licenses again after a European review judged the balance of benefit and risk unfavorable.5

That story is about kava medicines in Germany, not the drink poured at kava bars.

The ruleSkip kava if you have liver problems or take medicines that affect the liver. If you notice yellow skin or eyes, or brown urine, stop and see a doctor.430

Kava is the root of Piper methysticum, a pepper plant from the South Pacific. Which variety, which part of the plant and how it's made all change what's in your shell.

Researchers have since argued that water-based kava isn't automatically in the clear,13 so quality still counts. Ask the kavatender what's in the bowl: which kava, from where, and whether it's noble. Kava strains explains the varieties bars pour.

Bottom lineNoble kava, peeled root, mixed with water: that's the kava with the long track record, and the one FAO and WHO judged low risk.19

In a lab study, kava plus alcohol made people feel more impaired and perform worse than alcohol alone.21 Driving simulator studies found the same thing.24 NSW Health says the two together can cause intoxication, more drowsiness, slower reflexes and a higher risk of liver damage.10 The NIH says kava shouldn't be used with alcohol or other sedatives.2

The ruleNever mix kava with alcohol. Not before, not after, not in the same sitting.

Curious how the two compare otherwise? Kava vs alcohol goes side by side.

Sedatives. Kava adds to the effect of other things that slow you down, like benzodiazepines, barbiturates, sleeping pills and alcohol.210 One case report described a man who became lethargic and disoriented after taking kava with alprazolam (Xanax).20

Liver enzymes. In the lab, kava blocked several of the liver enzymes (cytochrome P450) that break down medicines.18 In people, a 28-day study found it slowed one of them, CYP2E1, by about 40%, and not the others it tested.19 Lab results and real life don't always match, which is why you ask.

Others to ask about. NSW Health lists possible interactions that still need study: levodopa (for Parkinson's), seizure medicines, MAO inhibitors, antipsychotics, blood thinners and antiplatelet drugs.10 Memorial Sloan Kettering also flags acetaminophen (Tylenol), based on lab studies, and advises stopping kava before surgery.22

The ruleTaking any medication? Talk to your doctor or pharmacist before you drink kava. If it affects the liver, skip kava.430

The NIH says kava may carry special risks during pregnancy and while breastfeeding, because of harmful compounds called pyrones.2 NSW Health doesn't recommend it, and notes kava can pass into breast milk.10 There are no human or animal studies of kava in pregnancy, and a 2024 case described a scaly rash in a mother and her newborn after heavy kava and kratom use during pregnancy.23

The ruleIf you're pregnant or nursing, skip kava.

NSW Health doesn't recommend driving or operating machinery after kava,10 and Memorial Sloan Kettering says it may impair your ability to drive.22

The research is mixed. One medicinal dose (180 mg of kavalactones) didn't impair simulated driving,26 but bar shells can carry far more, and FAO and WHO note that the effect of larger amounts isn't known.1 After a traditional session of more than 2,000 mg, people scored the same on tests even though they were visibly slower, and researchers called for more study.27 In Fiji, people who drove within 12 hours of drinking kava had about 4.7 times the odds of a serious-injury crash.25 In Iowa, police drug recognition experts documented four drivers impaired by kava.28

No one has tested a safe waiting time. If you feel it, don't drive: get a ride.

The ruleDon't drive impaired.

People who drink large amounts for a long time can get kava dermopathy: dry, scaly, sometimes yellowish skin.229 FAO and WHO found it in people drinking more than about 435 g of kava powder a week, along with weight loss, nausea, loss of appetite and indigestion, and consider these reversible once people stop.1 Heavy drinkers also tend to have a raised liver enzyme (GGT), which has returned to normal within one to two months off kava.115 NSW Health adds red eyes and tiredness to the list.10

Bottom lineIf your skin starts getting dry and flaky, that's your cue to cut back.

NSW Health says the evidence suggests kava isn't addictive, but that harmful, heavy use does happen in some places.10 In a 6-week trial, people on kava showed no more signs of withdrawal or addiction than people on placebo.16 Long-term research is thin.

Kratom is a different leaf. It comes from a tree in the coffee family, it can be habit-forming, with withdrawal when people stop, and some states restrict or ban it.3132 Lots of kava bars pour both, so check the menu. Kava vs kratom lays out the differences.

In recovery? Whether it fits your recovery is your call, and your program's. SAMHSA's National Helpline is free, confidential and open 24/7, in English and Spanish: 1-800-662-4357.34

Lots of regulars say they felt little the first time or two and more after a few visits. That's bar wisdom, not science: we didn't find a published study that tested it. The trials we did find looked at safety, not at how the feeling changes over time.16

Bottom lineDon't drink more on your first visit to chase a feeling. Go slow. You can always have another shell next time.

No health agency has set a safe amount. FAO and WHO say more data are needed to set one.1 For a sense of scale: the traditional drink uses about 1 to 1.5 g of root per 100 to 150 mL of water, a strong shell in Vanuatu carries roughly 250 mg of kavalactones, and a typical session there is 750 to 1,000 mg.1 The heavy-use problems above showed up at an average of 240 to 440 g of powder a week.1 Kava capsules, by comparison, usually top out at 250 mg a day.10 Bar shells vary a lot, so ask how strong they pour.

How kava bars tell you to drink it

• On an empty stomach, 3 to 4 hours after a meal.
• With water. Kava is a diuretic, so keep a glass of water going.
• One shell at a time. Give each one a while before the next. Blood levels peak 1.8 to 3 hours after drinking.10
• Know what rooted means. Rooted is bar slang for too much. It isn't like being drunk; you're more likely to feel heavy, a bit unsteady and a little nauseous. Stop, have some water and give it time.2130

Lots of kava bars have a First Time Guide: scan the code on the window or the bar and it walks you through your first shell.