medical specialty dealing with the development and care of children and with the diagnosis and treatment of childhood diseases (childhood disease and disorder). The first important review of childhood illness, an anonymous European work called The Children's Practice, dates from the 12th century. The specialized focus of pediatrics did not begin to emerge in Europe until the 18th century. The first specialized children's hospitals, such as the London Foundling Hospital, established in 1745, were opened at this time. These hospitals later became major centres for training in pediatrics, which began to be taught as a separate discipline in medical schools by the middle of the 19th century.

The major focus of early pediatrics was the treatment of infectious diseases that affected children. Thomas Sydenham (Sydenham, Thomas) in Britain had led the way with the first accurate descriptions of measles, scarlet fever, and other diseases in the 17th century. Clinical studies of childhood diseases proliferated throughout the 18th and 19th centuries, culminating in one of the first modern textbooks of pediatrics, published by Frédéric Rilliet and Antoine Barthez in France in 1838–43, but there was little that could be done to cure these diseases until the end of the 19th century. As childhood diseases came under control through the combined efforts of pediatricians, immunologists, and public-health workers, the focus of pediatrics began to change, and early in the 20th century the first well-child clinics were established to monitor and study the normal growth and development of children. By the mid-20th century, the use of antibiotics and vaccines had all but eliminated most serious infectious diseases of childhood in the developed world, and infant and child mortality had fallen to the lowest levels ever. In the last half of the century, pediatrics again expanded to incorporate the study of behavioral and social as well as specifically medical aspects of child health.