Piper methysticum, also known as kava, is a plant that grows in the Western Pacific and has been used by traditional cultures as a means of relaxation. Traditionally, the root has been prepared as a drink associated with sedative properties while maintaining mental clarity. More recently, extracts from the plant have been embraced by herbalists, touting the plants ability to treat anxiety.
The difficulty with herbal preparations is that they do not go through the same rigorous testing and validation that pharmacologic compounds do. Reports from communities where kava has been used have associated the compound with skin rashes
and eye irritation. Reports of liver toxicity in patients in Western countries taking supplements containing kava have also been reported. Several countries now have prohibitions on selling kava products because of this. Furthermore, additional studies now suggest that additional compounds found in the stem and leaves of the plant may be responsible for the liver toxicity. This combination seems to be particularly harmful in people who are heavy alcohol drinkers.
Overall, medications of any kind introduce the possibility for adverse reactions. Medications approved by the FDA are a safer option that potentially dangerous, unregulated supplements. If you are concerned about sleep or anxiety--both of which can be very disruptive to one's quality of life--it is best to discuss your concerns with your physician so that both medical and non-medical approaches can be considered. When it comes to medications, you are always safer taking anything with the supervision of a physician.