Costs were not discounted. Quantities and costs were not analysed separately. Costs were obtained by combining the acquisition price for each study drug with (1) the expenditure on those items required to administer the two drugs, (2) with the prices and administration costs of 'rescue' medication and medication used to treat adverse events and (3) with the material,nursing and medical time costs involved in caring for patients experiencing emesis or adverse events. Only health service costs were included in the analysis. Drug costs were derived from the monthly index of medical specialties (1991) and the British National Formulary. Material costs were derived from the Health Service Costings Returns (1986/7), with adjustments for inflation, and staff average hourly rates were obtained from the Department of Health.