Rickets, or vitamin D deficiency rickets, is a systemic, chronic, nutritional disease characterized by skeletal lesions due to vitamin D deficiency in infants, children and adolescents, causing disorders of calcium and phosphorus metabolism. Causes: (1) Perinatal vitamin D deficiency: If the mother does not supplement vitamin D during pregnancy, the newborn’s vitamin D quickly drops to the level of deficiency, so premature births and twin births are more likely to be deficient. (2) Insufficient sunlight or vitamin D supplementation in food: reduced outdoor activities and dislike of sunlight can affect the production of endogenous vitamin D, which can promote calcium absorption. (3) Fast growth rate: such as low weight, premature birth, twin births, disease and other factors, infants recover relatively faster growth and development, at this time, if the body does not have enough stored vitamin D, rickets is prone to occur. (4) Disease and drug effects: Gastrointestinal or hepatobiliary diseases affect vitamin D absorption, such as infantile hepatitis syndrome, chronic diarrhea, etc. Serious damage to the liver and kidneys can lead to vitamin D hydroxylation disorders, 1,25-OH2-D3 generation deficiency and cause rickets. The treatment of rickets is aimed at controlling the active period and preventing skeletal deformities. The specific measures include: (1) oral supplementation of vitamin D under the guidance of a physician, the general dose recommended is 2000-5000 IU per day for 4-6 weeks, after which it is changed to 400 IU/d for less than one year old and 600 IU/d for more than one year old, although high-dose vitamin D therapy is generally not recommended. (2) Calcium supplementation is advocated, with calcium and phosphorus supplementation from dietary milk, formula and soy products. (3) Enhance nutrition, ensure adequate milk intake, timely addition of foods for transition to lactation, and adhere to daily outdoor activities. Children with existing skeletal deformities in the post-transfer period should be strengthened with physical exercise, which can be corrected by active or passive exercise.