In a double-blind comparative study, 135 depressed patients were treated in 20 centers. Inclusion diagnoses were typical depressions with single episode (296.2), several episodes (296.3), depressive neurosis (300.4), and adjustment disorder with depressed mood (309.0) in accordance with DSM-III-R. The dosage was 3 x 300 mg hypericum extract LI 160 or 3 x 25 mg imipramine daily. The treatment lasted for 6 weeks. Main assessment criteria were the Hamilton Depression Scale (HAMD), the Depression Scale according to von Zerssen (D-S) and the Clinical Global Impressions (CGI). In both treatment groups, a parallel reduction of the Hamilton score from 20.2 to 8.8 (LI 160, n = 67) or from 19.4 to 10.7 (imipramine, n = 68), and the transformed D-S point values from 39.6 to 27.2 (LI 160) and 39.0 to 29.2 (imipramine) were found. The analysis of CGI revealed comparable results in both treatment groups. Clinically relevant changes of the safety parameters were not found. In the LI 160 group fewer and milder side effects were found as compared to imipramine.