A randomized trial was performed to test the hypothesis that, among patients with peripheral vascular disease, no difference is achieved in the magnitude of the reduction in blood cholesterol levels as a result of advice which is provided by a dietitian and that which is provided by a diet fact sheet. Fifty-nine patients were allocated at random either to a "dietitian" group (n = 31) or to a "diet fact sheet" group (n = 28). Dietary advice which was provided by a dietitian involved two personal interviews; the diet fact sheet was prepared by the NSW Department of Health. Twenty-two and 23 members of each group, respectively, returned for follow-up at three months. The mean cholesterol level fell by 8.5% among the "dietitian" group but only by 1.9% among the "diet fact sheet" group. The difference of 0.47 mmol/L in the total cholesterol level reduction between the two groups was statistically significant (P = 0.02; 95% confidence interval, -0.88 to -0.07 mmol/L). It appears that individual advice which is provided by a dietitian is more successful in leading to a reduction in blood cholesterol levels than is the administration of a diet fact sheet, even though this particular diet fact sheet appears to be excellent and is used widely. In view of the large numbers of patients and of persons in the population as a whole who would benefit from a reduction in blood cholesterol levels, and the expense of individual advice to be provided by a dietitian, explorations of cost-effective methods of providing dietary advice are needed.