This is a review of the literature on inhibitory effects of alcohol on activating systems and stimulation of synchronizing systems in the CNS. Inhibitory effects were seen as a sedation in the first half of night and worsening in the process of ethanol metabolism. Alcohol withdrawal after a long period of alcohol abuse often causes severe insomnia. Tolerance to hypnotic effect of alcohol as well as addiction and abuse are frequent in patients with insomnia who use it as sleeping aid. Correction of insomnia in alcoholics involves anticonvulsants and antidepressants in combination with cognitive-behavior therapy.