Epidemiologic studies of the incidence of emesis induced by narcotic analgesics are lacking. The histories of 260 cancer patients receiving oral narcotic analgesics prescribed at the Pain Clinic of our Institute from December 1988 to December 1989 were reviewed. Of the 260 patients, 120 were women, median age 61 (range 30-90) yr and 140 were men, median age 62 (range 30-82) yr. Nausea and vomiting associated with assumption of the various narcotics were buprenorphine 8.3% and 22.7%, morphine 18.3% and 28%, codeine 16.2% and 29.7%, and oxycodone 10% and 40%, respectively. Since the use of narcotic analgesics can effectively relieve pain and improve quality of life in cancer patients, it is important to be aware of the incidence of narcotic-induced emesis in order to use appropriate prophylactic antiemetic therapy.