Hypnotic drugs induce sleep[1] (which differentiates them from the sedative category), used in the treatment of insomnia and in surgical anesthesia. Often the treatment of insomnia will not begin with drugs at all. Since many hypnotic drugs are habit-forming, a physician will usually recommend alternative sleeping patterns, sleep hygiene, and exercise before prescribing medication for sleep, due to a large number of factors known to disturb the human sleep pattern.
Melatonin, a hormone, can work as a hypnotic if taken 30-90 minutes before usual bedtime.
Alcohol is also used as a hypnotic drug, though not medically. To quote the British National Formulary: "Alcohol is a poor hypnotic because its diuretic action interferes with sleep during the latter part of the night. Alcohol also disturbs sleep patterns, and so can worsen sleep disorders"