We investigated the lipid peroxidation in depression by determining the markers of this process: melondialdehide, total SH groups and catalase. We used blood samples from inpatients with specific psychiatric symptoms. The medication consist of hypnotic nitrazepam and antidepressant trazodone, using film-coated tablets trazolon, 50 mg once a day, three weeks. In the second part of our experiment, we studied the antioxidant properties of trazodone, using blood samples from healthy subjects. It remain to establish if the free radicals are responsible for the initiation of depression or not.