A large quantity of research concerning issues of patient compliance with medications has been produced in recent years. The assumption in much of this work is that patients have little option but to comply with the advice and instructions they receive. Studies have shown, however, that between one third and one half of all patients are non-compliant, but different authors cite different reasons for this high level of non-compliance. In this paper, the concept of compliance is questioned. It is shown to be largely irrelevant to patients who carry out a 'cost-benefit' analysis of each treatment, weighing up the costs/risks of each treatment against the benefits as they perceive them. Their perceptions and the personal and social circumstances within which they live are shown to be crucial to their decision-making. Thus an apparently irrational act of non-compliance (from the doctor's point of view) may be a very rational action when seen from the patient's point of view. The solution to the waste of resources inherent in non-compliance lies not in attempting to increase patient compliance per se, but in the development of more open, co-operative doctor-patient relationships.