Any of several plants of the genus Piper, as cubeb, betel, and kava.
Investigate the benefits of chamomile, valerian, kava, passionflower, skullcap, catnip, or hops.
When visiting a village, you are expected to arrive bearing a large, grubby kava root. Kava is Fiji's traditional drink, which, in my neophyte opinion, tastes of disinfectant and month-old dishwater.
If you already are suffering from liver disease, or are taking meds that increase the sensitivity of your liver, talk to you doctor before starting a kava regimen.
