Overtreatment refers to interventions that do not benefit the patient, or where the risk of harm from the intervention is likely to outweigh any benefit the patient will receive. It can account for up to 30% of health care costs, and is increasingly recognised as a widespread problem across nations and within clinical and scientific communities. There are a number of inter-related factors that drive overtreatment including the expanding definition of diseases, advertising and the influence of the pharmaceutical industry, how (...) doctors are trained and remunerated, demands from patients and the fear of complaints leading doctors to practise defensively.This paper discusses a number of ethical and practical issues arising from overtreatment that doctors and patients should be aware of. It also considers the flow-on effects of overtreatment such as the increased cost of care, increase in work load for health professionals, and wastage as resources are diverted from more genuine and pressing needs. In addition, there are references to a number of Medical Council of New Zealand statements about what good medical practice means in an environment of resource limitation. The paper concludes with a few measures that doctors and patients could take to reduce overtreatment but acknowledges that health care is extremely complex so it would be unrealistic to eliminate overtreatment entirely. (shrink)