Rickets is a very common systemic deficiency of vitamin D in infancy. There are many reasons for rickets, such as insufficient sunlight, insufficient intake, excessive growth rate, disease factors, drug effects, etc. 1, insufficient sunlight: rickets is mainly caused by vitamin D deficiency in the body. Tall buildings in large cities or atmospheric pollution will block sunlight and ultraviolet rays. Therefore, it is easy to cause the lack of vitamin D in the body. 2, insufficient intake: if the child does not get enough vitamin D intake in the growing stage, prone to rickets. 3, too fast growth: rickets also occurs in premature or twin-born babies, because the body does not have enough stored vitamin D. After birth, due to the rapid growth rate, too much vitamin D is needed, which can cause vitamin D deficiency rickets. 4, disease factors: if the infant suffers from hepatitis syndrome. Steatorrhea, pancreatitis, severe liver and kidney damage, and other intestinal and hepatobiliary diseases can affect the absorption of vitamin D in the organism. 5, drug influence: If the body long-term use of anticonvulsant drugs will lead to vitamin D deficiency in the body, common anticonvulsant drugs are phenobarbital, phenytoin sodium, etc.. The main causes of rickets are as above five. Therefore, it is important to increase the intake of vitamin D in the development of the organism to prevent rickets from occurring.