Since there continues to be a high incidence of postoperative nausea and vomiting associated with many types of surgery, and the standard antiemetics often do not achieve satisfactory results, there have been attempts to use the 5-HT3 antagonists. This group of substances is relatively new, but has already been used successfully as an antiemetic during chemotherapy. To date, results are on hand for four different 5-HT3 receptor blockers: ondansetron, tropisetron, granisetron and dolasetron. Applied intravenously, all four have been effective both in prophylaxis and also as therapy for postoperative emesis. Except for ondansetron, there is so far no definitely clear knowledge about the lowest possible effective dosage. The entire group is well tolerated: only occasional and minor side effects have been reported. Even though not all the hopes originally set in the 5-HT3 group of antagonists have been fulfilled, progress has nevertheless been achieved. Especially noteworthy points are a positive cost-effectiveness relationship of these drugs and their appropriate use in case of the proper indications.