Over a period of 10 years, 645 patients were treated with six different betasympathomimetics because of threatening premature labor during the 24-36 weeks of gestation. Some 603 comparable patients were analysed with various parameters to find the most suitable criterion for assessing the efficacy of tocolysis and the best tocolytic agent. Delivery after 37 completed weeks proved clinically a sufficient criterion of a successful therapeutic outcome. The various scores did not essentially facilitate comparison of various tocolytics. The combination buphenin (DilaverR) + verapamil (IsoptinR) proved to be the most suitable medication.