Vitamin D is an essential nutrient for the maintenance of life and it is one of the most important biological regulators of calcium metabolism. Its deficiency can lead to disorders of calcium and phosphorus metabolism in the body and disorders of bone calcification as the main characteristics of the disease. Vitamin D is produced by the skin itself through sun exposure and ingested through complementary foods. Vitamin D deficiency can lead to skeletal changes, muscle relaxation, and psychoneurological symptoms. In severe cases, it can affect the digestive, respiratory, circulatory, and immune systems, as well as the mental development of children. Vitamin D deficiency eventually leads to rickets. Before becoming rickets, children with vitamin D deficiency aggravates, calcium in the body continues to be abnormal will gradually appear a variety of characteristic clinical manifestations: early psychoneurological symptoms, the child has sleep disturbance, crying, easy to sweat and other phenomena, sweating scalp itchy and shaking his head on the pillow rubbing, appearing occipital baldness. Appearance of the above symptoms has been to the mothers alarm lack of vitamin D and calcium, at this time immediately supplement vitamin D and calcium, all the symptoms will be relieved immediately; if you do not pay attention to, indifferent, and gradually the child’s head will grow into a square head, the sternum into a “chicken chest”, “rib margins outward turning The child’s head will gradually become a square head, the sternum will become a “chicken chest”, and the “rib margins will be turned out”, and the legs will become “O” or “X” shaped legs. The muscles are flabby, the abdomen is enlarged, the expression is indifferent, the speech is slow, the immunity is low, and the infection is repeated. By this time, even if the treatment saves lives, the deformity of the doll’s skeleton is irreversible. What mother would forgive herself for raising her baby like that? The good thing is that this disease can be prevented, and the method is simple and easy to implement: 1, adhere to breastfeeding, add complementary foods on time (food containing vitamin D, animal liver, egg yolks, etc.) 2, routine supplementation of Icosin (1 month after birth to start taking Icosin, one capsule a day, until 1 ½ to 2 years old.) 3.Stay in the sun.