AbstractTolerability of CGP 4718 A (sercloremine), a 4‐(5‐chloro‐2‐benzofuranyl)‐1‐methyl‐piperdine, as well as the effects on target symptoms in 22 hospitalized depressed patients, were investigated in an open, multicenter study. In daily doses of 50 to 150 mg, the compound was well tolerated. There were no changes in cardiovascular parameters (blood pressure, ECG) nor were there changes in laboratory values that could be considered of clinical relevance. Of concern, however, were sleep disturbances, which appeared to be aggravated in the majority of treated patients. There were only a few other side‐effects that could be related to the drug treatment, and they were mostly mild and transitory. The therapeutic effects of CGP 4718 A, as judged by the changes in total Hamilton depression rating scores and global assessement, indicated beneficial action of the drug on the core symptoms of depression (except sleep disturbances). The therapeutic effect appeared to be dose‐related and particularly marked in neurotic and reactive depressions. These findings, in line with the predictions made on the basis of preclinical animal studies, encourage further clinical testing of this compound.