In a double-blind placebo-controlled comparative study, 180 female patients were randomly assigned to groups and treated approximately 3 h before dilatation and curettage with either a single 1 mg vaginal suppository of Gemeprost or a matching placebo. The patient population included premenopausal non-pregnant or postmenopausal patients presenting at four participating centers in West Germany. Patients were monitored from the time of drug administration to approximately 24 h after the operation. A marked response to treatment with Gemeprost was noted at the general cervical assessment performed immediately prior to dilatation. A significant increase in diameter of the cervical canal was observed and subsequent mechanical dilatation was found to be significantly easier as a result of Gemeprost treatment. No differences between the response to treatment in premenopausal and postmenopausal patients were found in our interim analysis of 113 patients. The incidence of preoperative uterine pain increased with time as a result of Gemeprost treatment but it was predominantly mild and no analgesics were required. Gastrointestinal side-effects were rare and well tolerated in both treatment groups. This study indicates that Gemeprost is an effective, well tolerated preoperative cervical dilator/softener in non-pregnant patients.