Alprazolam is one of the most commonly prescribed psychotropics drug all over the world. This suggests that alprazolam is very effective and safe. A multicentre clinical trial was carried out for assessing its efficacy and side effects. 130 patients suffering from anxiety disorders, mixed anxiety and depressive disorders and dysthtymia were involved in the trial. During 6 weeks they used to take from 1.5 to 2.5 mg. of alprazolam daily. Mental state has been assessed with Hamilton rating scales of anxiety and depression, Montgomery Asberg scale of depression and CGI scales. At the endpoint good recovery was found in 75% of the patients, mild recovery in 19%, and 6% got worse. The effect of treatment depends on individual patients' traits rather than on initial mental state. Adverse events were noted in a half of patients, were not severe and were going down during the treatment. 4.6% of patients dropped out because of adverse events, the others tolerated alprazolam well.