Giantism is a disorder that occurs before puberty and is caused by hyperactivity of the anterior pituitary gland and high secretion of growth hormone. Due to the excessive secretion of growth hormone by the pituitary gland before puberty, the adolescent’s bone scale is not closed, forming gigantism. If the bone scale has fused after puberty, acromegaly is formed. In a small number of cases, the onset of the disease in adolescence continues to develop into adulthood to form gigantism. Such patients not only have a large physique, but also have a generalized hypertrophy of internal organs. Many giants are tall and most have acromegaly, but in old age, their physical strength declines and they age more rapidly than the average person. The onset of gigantism is slow, and there may be no symptoms in the early stages. Gradually, facial growth and widening, giant nose and ears, sparse teeth, blunt speech, thickening of the skin, excessive sweating and fat, etc., may occur, while men may have an increased libido and women may have menstrual disorders, amenorrhea, and infertility. Pituitary gigantism manifests as excessive growth in children, osteoporosis, and particularly rapid growth of the extremities. It can be determined by GH measurement, significantly elevated growth hormone, elevated blood glucose, and reduced glucose tolerance, and whether it is gigantism can be determined by x-ray examination. The causes of excessive growth hormone production are pituitary and extra-pituitary.