Breast cancer patients and patients with Hodgkin's disease (N = 663) were contacted initially by medical specialists at 15 medical centers across The Netherlands and subsequently 498 of them were interviewed in their homes in order to examine interactions between their personality characteristics, their assessment of the adequacy of information feedback from their physicians about their illness, its treatment and prognosis, and their adoption of an unproven diet remedy. The data indicate that patients who believed they had received insufficient and unclear information were more likely to be adopters of the Moerman diet than patients who believed the information was adequate. Personality moderator analyses indicated further that the relationship between information adequacy and diet adoption held specifically for those patients with high trait anxiety, low self-esteem, angry-aggressive coping styles or impulsive attitudes. The discussion focused on rational and irrational elements in physician-patient communications, the strategies available to physicians to improve their communication skills, the desirability of constructing and distributing educational and informational materials for use by patients, and the need for physicians to offer their patients an opportunity for contact with companions in distress.