Cancer and its treatment are known to cause malnutrition in significant numbers of patients. Although a variety of contributory factors have been identified it is clear that the aetiology of malnutrition is complex and multifactorial. Taste aberrations are believed to be amongst the causative factors and to contribute to the development of food avoidance/aversion in affected patients. The study described investigates the incidence of food avoidance in a random sample of 72 patients undergoing cancer chemotherapy. The results show that 59 (82%) had avoided one or more foods since the instigation of treatment. The foods most commonly affected were coffee, tea, citrus fruit, chocolate and red meat. Changes were noted in the consumption of both sweet and salty foods. In terms of food avoidance no apparent relationships were demonstrated between its incidence and either the type of disease or the drugs used in therapy. In men, the pattern of avoidance showed no differences between the younger (up to 49 years) and older (50 years and older) patients; marked differences were observed between younger and older women. Although the foods avoided in general have little nutritional implication their omission may affect the quality of the patient's life. Food avoidance per se may, however, affect nutritional status; suggestions for overcoming its effects are made. The results of this study, obtained by subjective assessment of food acceptability, highlight the individual nature of food avoidance in affected patients and suggest that each must be individually assessed if appropriate nutritional advice is to be given.