A system was devised to establish the optimum treatment for emesis for each individual child receiving cytotoxic treatment. Cytotoxic drugs were ranked on a scale (1-5), with antiemetic regimens correspondingly graded. An age division (less than or equal to 5 years, >5 years) was included. Cytotoxic treatment was given with coadministration of the parallel antiemetic regimen. Failure to control emesis required administrtion of a stronger regimen as defined in the guidelines. A prospective clinical audit was performed to monitor the efficacy and utility of the system using diary cards to record episodes of nausea or vomiting, or both, completed by the patient or a parent and the nursing staff. The following audit criteria were set: (a) 80% control with first courses of chemotherapy; (b) 85% control with subsequent courses of similar chemotherapy; and (c) 90% lack of anticipatory nausea. Sixty children (<18 years) received emetogenic cytotoxic drugs from February-June 1993. The criteria were satisfied in two of three categories, with 82% control for first courses of chemotherapy, 83% control for subsequent courses of chemotherapy, and 90% lack of anticipatory nausea. The guidelines were workable and acceptable overall. Minor modifications have been made subsequent to the audit to improve their efficacy further.