A double-blind, placebo-controlled study with syntocinon (oxytocin) was carried out in 12 patients, nine females and three males with obsessive compulsive disorder (OCD). Patients were treated by intranasal administration of oxytocin spray (18 IU per day) or placebo. No reductions in the number of obsessions or compulsive behaviors were observed in either treatment group. To evaluate whether a higher dosage would exert more beneficial effects, two additional patients were treated with a threefold higher dosage of oxytocin using an open design. In one patient a slight reduction in the number of checking rituals was observed, whereas in the other patient virtually no effect was observed. The results of this study do not support the hypothesis that oxytocin might be a potential anticompulsive agent.