The incidence of postoperative vomiting was studied during a 10-week period in a recovery room. Vomiting occurred in 520 (23%) of the 2,230 cases. Often it was limited to one or two episodes as the reflexes became active. Only in 3% of the patients was it severe enough to be considered as calling for drug therapy. In nearly every case the vomiting was thus controlled. The hydrochlorides of promethazine, triflupromazine, and trimethobenzamide were equally effective. During the past 10 years antiemetic drugs have been administered routinely before anesthesia as prophylaxis against anticipated vomiting, but in the opinion of the authors the facts do not justify the routine use of antiemetics for this purpose.