Endocrinology is a complex study of the various hormones and their actions and disorders in the body. Glands are organs that produce hormones. These are substances that help to control activities in the body and have several effects on the metabolism, reproduction, food absorption and utilization, growth and development etc. The glands that make up the endocrine system include the pineal, hypothalamus, pituitary, thyroid, parathyroid, thymus, adrenals, pancreas, ovaries and testes.

An endocrinologist is a specially trained doctor who has training in Internal Medicine as well.