Kava is a Polynesian herb, often referred to as a herbal anti-depressant. The herbal medicine interacts with voltage-gated ion channels in the brain to effectively alter levels of neuronal excitation, leading to muscle relaxant, anaesthetic, anxiolytic and anti-convulsive effects. The pharmacological properties that result from ingestion of Kava can be attributed to a group of compounds called Kavalactones.

Kava has been consumed in the Pacific islands for centuries mainly during ceremonies, and otherwise for its tranquillising effects. It is prepared by crushing fresh or dried roots or stems of the kava shrub Piper methysticum, and creating an emulsion, which is then consumed as a beverage. The consumption of kava has become controversial in recent years, following reports of resulting hepatotoxicity, which has led to many countries regulating its use. These reports have seen further studies and clinical trials conducted to elucidate the nature of the alleged liver damage suffered by users, and whether the specific extraction or formulation protocols used in these incidences is responsible for the damage. 

Recent studies on the mechanism of action of isolated Kavalactones have discovered that these compounds may exhibit neuroprotective properties, indicating that kava could be useful in the treatment of degenerative diseases and conditions associated with the nervous system.