preventive medicine, branch of medicine dealing with the prevention of disease and the maintenance of good health practices. Until recently preventive medicine was largely the domain of the U.S. Public Health Service or state and local health departments, but it has become an important consideration of health maintenance organizations, private practitioners, and other health care providers. Preventive medicine encompasses such activities as research into causes of disease; vaccination against those diseases for which the causes are known, e.g., poliomyelitis, influenza, and measles; studies of environmental deterrents to health; and instruction in public health and hygiene. See also eugenics.

Efforts toward disease prevention in the community and the individual. It covers patient interviews and testing to detect risk factors; sanitary measures in homes, communities, and medical facilities; patient education; and diet and exercise programs as well as preventive drugs and surgery. It has three levels: primary (e.g., prevention of coronary heart disease in a healthy person), secondary (e.g., prevention of heart attack in a person with heart disease), and tertiary (e.g., prevention of disability and death after a heart attack). The first is by far the most economical. Important advances in preventive medicine include vaccination (see vaccine), antibiotics, diagnostic imaging, and recognition of psychological factors. Seealso epidemiology, immunology, industrial medicine, quarantine.

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