OBJECTIVE To assess the patterns of alternative medicine use in patients of a public hospital oncology unit, and to compare patients' experience of alternative with conventional medicine. METHODS Self-administered questionnaire survey of cancer patients attending specialist consulting rooms at the Royal North Shore Hospital and the Oncology Outpatient Clinic at Port Macquarie Base Hospital during August 1995. METHODS 507 patients attended the clinics; 335 (66%) returned questionnaires, of which 319 (62%) were sufficiently complete for analysis. METHODS Expectations of and satisfaction with both conventional and alternative treatment, use of alternative treatment, and patient characteristics associated with this use. RESULTS Expectations of and satisfaction with both conventional and alternative treatment were very high. Alternative treatments (most commonly dietary and psychological methods) were used by 21.9% of patients. Median annual cost of alternative therapy was $530, with most patients reporting "value for money". Younger age and being married were positively associated, and satisfaction with conventional treatment was negatively associated, with alternative medicine use; 40% of patients did not discuss alternative medicine with their physician. CONCLUSIONS A significant proportion of cancer patients use one or more forms of alternative therapy. The use of alternative therapy may reflect on deficiencies in the current standard of care.