We have compared the efficacy of granisetron in combination with dexamethasone with each drug alone in the prevention of postoperative nausea and vomiting (PONV) after middle ear surgery. In a randomized, double-blind study, 120 patients (85 females) received granisetron 3 mg, dexamethasone 8 mg or granisetron 3 mg with dexamethasone 8 mg i.v. (n = 40 in each group), immediately before induction of anaesthesia. A standardized general anaesthetic technique was used. A complete response, defined as no PONV and no need for another rescue antiemetic during the first 3 h after anaesthesia, was recorded in 83%, 50% and 98% of patients who had received granisetron, dexamethasone and granisetron-dexamethasone, respectively. The corresponding incidences during the next 21 h after anaesthesia were 80%, 55% and 98% (P < 0.05; overall Fisher's exact probability test). In summary, prophylactic use of combined granisetron and dexamethasone was more effective than each antiemetic alone for the prevention of PONV after middle ear surgery.