Effects of kavalactones include mild sedation and a slight numbing of the gums and mouth. Kava has been reported to improve cognitive performance and promote a cheerful mood. Kava has similar effects to benzodiazepine medications,without its bad side effect, including muscle relaxant, anaesthetic, anticonvulsive and anxiolytic effects.

In a traditional setting, a moderately potent kava drink causes effects within 20–30 minutes that last for about two and a half hours.
The sensations, in order of appearance, are slight tongue and lip numbing mildly talkative and sociable behavior; clear thinking; calmness; relaxed muscles; and a sense of well-being.
The effects of a kava drink vary widely with the particular selection of kava plant(s) and amount. A potent drink results in a faster onset with a lack of stimulation; the user's eyes become sensitive to light, the person soon becomes somnolent and then has deep, dreamless sleep within 30 minutes. Sleep is often restful and there are pronounced periods of sleepiness correlating to the amount and potency of kava consumed. After wakening the drinker does not experience any mental or physical after effects. However, this sleep has been reported as extremely restful and the user often wakes up more stimulated than he or she normally would.