The purpose of this paper was to review evidence related to the effectiveness of systematic interventions in preventing or detecting and treating delirium. The review process involved a systematic search of the literature on each topic, assessment of the validity of the studies retrieved and examination of their results. The literature search identified 10 studies on prevention and 7 studies on detection and treatment. A broad spectrum of systematic interventions appeared to be modestly effective in preventing delirium in young and old surgical patients but not elderly medical patients. Systematic detection and treatment programs and special nursing care appeared to add large benefits to traditional medical care in young and old surgical patients and modest benefits in elderly medical patients; however, it seemed that the more precise the target of the detection and treatment program, the greater the benefit.