In the early 2000s, kava was banned for sale in Europe due to widespread concerns that use of kava herbal supplements might have toxic side effects on the liver. However, regarding the list of kava kava side effects liver toxicity has never surfaced in people who consumed a properly prepared dose of kava, i.e. an extraction of root material only. The European panic about kava kava’s side effects on the liver was based on a small German-Swiss study of about 30 people who fell ill with liver damage after regular use of an herbal kava extract, a study which suffered from several complicating factors which led later researchers to debunk its initial findings.

The original German study, incidentally conducted by Merck Pharmaceuticals, found indications of liver damage including weight loss and malnutrition in 30 subjects who had been using kava extract regularly over a period of a few months. However, literature reviews of the study discovered that a large portion of subjects in the sample were also frequently consuming alcohol and/or prescription drugs metabolized by the liver. Later research in this area has suggested that kava can have harmful effects on the liver when it is used in combination with alcohol and liver-affecting drugs. Furthermore, new evidence has suggested that the kava extracts used by subjects in the study had been made with leaves, stems and bark peelings from the aerial parts of the plant, which do contain toxic alkaloids and are never used in traditional kava preparations. In light of these new findings, in 2008 the European Union lifted its 2001 ban on the sale of kava.

However, this doesn’t mean that every kava product out there automatically comes without the risk of liver side effects. In a global kava market with such a proliferation of vendors, it’s still often up to the customer to find a kava product that will be both effective and safe for them to use. Simple kava products, such as the whole dried root or a straight kava root powder, tend to be very safe for use because they have been minimally processed. One of the problems with more refined kava extracts and pills is the difficulty of determining exactly what’s in them: certain vendors use heavy solvents like alcohol or acetone to extract kavalactones, leaving behind chemical traces in the finished product. Look for vendors who have taken the time to describe their extraction process, and who specifically state that they only use kava root in their extracts and not the leaves or stems.

One safer method of kavalactone extraction is cold CO2 extraction, a fairly recent technique which creates a potent full-spectrum kavalactone paste. More and more, sophisticated kava vendors are beginning to offer full-spectrum kava extracts and pastes— not only because of their enhanced potency, but also in response to studies that suggest full-spectrum extracts may deliver a protective effect on the liver compared to extractions that contain only a few kavalactones. For instance, along with its 18 types of active kavalactones, a full spectrum kava root extract also contains glutathione, a tripeptide antioxidant also found endogenously in human liver cells. In the liver, glutathione protects liver cells from oxidant damage. While solvent processes using alcohol or acetone do not extract glutathione, traditional kava brews, in which the root matter is suspended in water, do contain glutathione. Where the full-spectrum issue gets really interesting is that among the 18 types of active kavalactones found in the vertical root of kava, one of them, flavokawain B, may be hard on the liver in isolation. However, in traditional preparations of kava or a full spectrum extract which contains the root’s full chemical profile, the presence of glutathione seems to have a protective effect on users’ liver cells.

If you take kava in moderation and avoid combining it with other substances that place a load on the liver, side effects of kava tend to be mild and even enjoyable, usually limited to a slight lack of coordination similar to mild alcohol intoxication. Kava root side effects from heavier, prolonged use (drinking a few bowls a day over a few weeks or months) include eye itchiness or irritation, shortness of breath, puffiness in the face, and the eponymous kava dermopathy— an acquired skin condition where the skin becomes slightly rough and scaly. All of these side effects are mild and will reverse if a person takes a break from using kava for a little while or decreases their average dose. In fact, acquired kava dermopathy was even considered a status symbol in ancient Hawaii because it demonstrated that a person had reliable access to large amounts of the prestigious kava brew!

Here are a few simple guidelines if you want to use kava but avoid incurring side effects on your liver: use a small amount of kava the first few times you try it, in order to gradually introduce the plant’s novel alkaloids into your body. Avoid combining kava with any drugs that interact with the liver or alcoholic drinks. Always consult your doctor before using kava if you have an existing liver condition or take medications that interact with the liver. Additionally, because kavalactones affect neural pathways in the brain to generate relaxing and anxiolytic effects, kava can interact in harmful ways with prescription medications that also work on these neural pathways. These include sleep medications like diazepine, anti-convulsants, anti-anxiety drugs, anti-psychotics, and levodopa to treat Parkinson’s disease. This is not a comprehensive list, but in general it’s advisable to check with your doctor about kava’s safety for you if you take any drugs that affect the central nervous system.

Kava kava is one of the best documented and researched herbs for both safety and effectiveness, and has been used by native islanders and now consumers worldwide for many years with beneficial results. Providing it is not combined with alcohol or drugs such as those above, a roots-only kava brew or product can have wonderful healing properties with virtually no side effects, which you can take anytime you feel you could use a dose of tranquility. It will be even more relaxing knowing that your liver is happy too!