The traditional ceremonial drink made from the 'Ava root has a sedative effect. Not quite like alcohol, but you can lose feelings in your legs and be quite sedative if you have too much.
In the old days the village taupou chewed the Ava root and spit it out into the Kava bowl and when there was enough it was served in a coconut shell cup to each man in order of rank.
Now the same ceremony can be seen, but the root is usually pounded rather than chewed.
Some health stores carry Kava root for health purposes.