A large part of our clinical work is the health care and conditioning of children, and although most of us are related to Chinese medicine, things about cod liver oil supplementation are still of concern to all mothers, so let’s talk to you about it. In 2016, the Editorial Board of the Chinese Journal of Pediatrics, the Pediatric Health Group of the Chinese Medical Association, and the Neonatology Group of the Chinese Medical Association published the “Recommendations for feeding preterm and low birth weight infants after discharge from the hospital”, which pointed out that since both fat-soluble and water-soluble vitamins in human milk are difficult to meet the needs of preterm infants to catch up with growth, especially vitamin A and vitamin D. Therefore, the recommendations The recommendations emphasize that preterm and low birth weight infants should receive vitamin D supplementation of 800-1000 IU/d immediately after birth, changing to 400 IU/d after 3 months of age until 2 years of age, while the recommended vitamin A intake for preterm infants is 1332-3330 IU/(kg?d), which can be supplemented at the lower limit after discharge from the hospital. Not only preterm and low birth weight infants have serious vitamin A and D deficiencies, but epidemiological surveys in recent years have shown that vitamin A and D deficiencies are common among infants and children in China. Vitamin A deficiency in children under 5 years of age in poor rural areas of six western provinces of China is a severe deficiency, and the proportion of vitamin A deficiency (vitamin AD) in hospitalized newborns in the Children’s Hospital of Chongqing Medical University is as high as 96.4%, with the lowest serum vitamin A in the 0-1 year old group and the lowest 25-(OH)D in the 7-14 year old group in the resident Beijing urban area, and the detection rate of vitamin AD deficiency in all examined young children is 43.84%. The detection rate of vitamin AD deficiency was 43.84% and the detection rate of vitamin D deficiency was 80.17%. To summarize, infants and young children grow and develop rapidly, but their diets are relatively homogeneous and they cannot get as much nutrients from food as adults. In addition, infants and young children have limited stomach capacity and low intake of complementary foods, while carotenoids, which have low absorption and conversion rates, can only be absorbed in the presence of lipids. Therefore, a daily preventive dose of vitamin AD can effectively supplement the missing vitamins A and D in the diet to maintain normal physiological functions and promote healthy growth of infants and young children.