Medical is the field of health care and healing, which encompasses many aspects of life and wellbeing. Conventional modern medicine uses drugs and surgery, often in conjunction with counseling, lifestyle measures, and dietary or herbal remedies. Alternative and complementary medicines are also part of this field. The term physician refers to doctors and other specialists who are trained in medicine, but nurses and therapists working within healthcare systems are known as clinicians.

Medical studies are concerned with the origin, diagnosis, prevention, cure and treatment of disease. Historically, medical knowledge was acquired by observing and learning from the practices of healers and physicians in the context of cultural and social institutions. This led to the development of a wide range of medical disciplines, including anatomy, physiology, pathology, microbiology, pharmacology, biomedical engineering, anthropology and public health.

Health care systems, hospitals and clinics vary widely around the world, and medical practice is subject to laws and policies governing access to healthcare and reimbursement for services. Most developed nations have national health insurance plans that provide a wide variety of services to their citizens at little or no cost. However, these systems have many critics who argue that they are not efficient and effective in meeting the health needs of society.

Contemporary medical research is conducted in the fields of chemistry, biology, genetics, physics and mathematics. This scientific knowledge contributes to new medical treatments and diagnostic procedures, as well as advancing public health and medical education.

The earliest records of medical science date back to prehistoric cultures who used plants (herbalism), animal parts and minerals in their treatments, which was often linked to spiritual beliefs such as animism, spiritualism or shamanism.

In the Middle Ages, medical knowledge increased with the development of universities, and the ancient Greek physician Hippocrates established the Hippocratic Oath for physicians. The era of modern medicine began with Edward Jenner’s smallpox vaccine in the 18th century, Robert Koch’s discovery of bacteria and the advent of antibiotics in the 20th century.

There are numerous subfields of medicine, including obstetrics and gynecology, endocrinology, cytology, immunology and histology. Other important areas are virology, epidemiology and pharmacology, with the latter concerned with the interaction between drugs and their effects on the body. Other areas include clinical pharmacology, which aims to improve the safety and efficacy of drug therapies, and psychopharmacology, which is helping to bring psychiatry out of its current status as an adjunct to medicine into a fully fledged medical discipline.