Research Summary: Perspectives on the Toxicology of Kava

Picture of Kavahana

In 2015, a study was published by the University of Hawa’ii reviewing kavas benefits and discussing the claims of its toxicity. The review was done by researchers both from the Pacific Islands and Western countries to present different perspectives on the claims. This comes in response to increased bans and restrictions of kava in Europe in response to reported liver damage caused by kava, which has since been invalidated. 

Traditional uses of kava and the changes in modern consumption

Traditionally, kava has been used socially for personal and community traditions in the pacific islands. It’s prepared into a tea by using dried, ground powder from the kava roots submerged in water. This releases the kavalactones, which are the active ingredients of the kava. While the cultural practices and uses continue to evolve, there is a certain awareness and appreciation for the communal and traditional aspects of the drink.  As use expands globally, there have been other uses for kava emerge. While it continues to be drunk socially, its health benefits are also becoming well known. It has been classified as a natural health product in the United States and other countries. Modern kava bars are gaining in popularity which is changing how kava is consumed. While almost all kava is grown in the pacific islands, global demand is adding pressure to local farmers and adding to kava supplements on the market they may not be of high quality.

Recent progress in Kava Toxicology

The study reviewed a variety of studies in both clinical and experimental (animal) settings. The results varied which could be due to confounding factors and type of extract used in the study. There was a presented genetic component to the risk of kava toxicology, but more research is needed to understand this. Interaction with other compounds and medications seems to be where the risk is highest. Due to its calming effects on the brain, there is some concern about drug interactions with medications that work on the central nervous system (the brain and spinal cord). There is already understanding of the negative effects in combining alcohol with kava. Another big concern is the strain and preparation. Traditionally, the kava drink is prepared using only the kava root. It’s been reported that using other parts of the plant (the leaves and stems) can contain less desired kavalactones leading to negative effects and potential risk of toxicity.

The Benefits of Using Kava

There is a long list of health benefits kava has been used for throughout history. In Pacific Island medicine it’s been to help treat conditions like anxiety, stress and depression as well as urinary issues, menstrual problems and menopause symptoms, respiratory illnesses (eg. asthma and TB), gastrointestinal issues and skin conditions. These traditional uses have indicated that kava strain, plant part and preparation are important considerations in treatment. In western cultures kava has been most used to help treat stress and anxiety, sleep disorders, mild anxiety, and menopausal symptoms. There have even been clinical trials that show Kava is more effective than placebos in treating anxiety. Some studies have even shown anti-cancer effects, though more research is needed to better understand this.


Connecting Western and Pacific Island perspectives has given us a broad spectrum view of the question of kava’s toxicity and benefits. Key things to consider are the kava strain and extraction, which will impact the number and type of kavalactones present. Western kava use suggests toxicity is rare with very low incidence. Most studies that found a toxic effect of kava involved other medications or substances.  In Pacific Island cultures, kava toxicity is unheard of as there are no reported cases. There is the chance that this is due to under reporting or lack of public health data. There is the idea that there is an “entourage” effect of kava suggesting other compounds, besides kavalactones, that play a role in its effects that aren’t well understood.

While traditional and cultural considerations are important and relevant, Western cultures need to be mindful of how kava is prepared and the type of kava they are taking to be sure they have the best experience. 

Contemporary Pacific and Western perspectives on `awa (Piper methysticum) toxicology 

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Research Summary: Perspectives on the Toxicology of Kava


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