The twenty-first century will be the era of the market economy, a century char acterized by the penetration of market forces into every social field, even into government activities, education, and medical care. Guidelines for the provision of clinical care have been developed in recent years chiefly in American health-care services, which are the most thoroughly exposed to the market economy. The problem of escalating medical costs in the United States led the government and consumer groups to introduce clinical practice guidelines. Guidelines were introduced to control medical costs and quality. Initially, guidelines were developed mainly on the consumer side, but professionals, too, soon recognized the importance of clinical practice guidelines. The involvement of diverse groups in the development of guidelines has inten sified the need to create and improve scientific methods for drawing up those guidelines. Owing to the development of systematic and structured abstraction methods, evidence-based guidelines have been proposed. Principally, guidelines are a sum mary of published treatments created by statistical analysis of clinical outcomes.