Anna had a baby for six months and was still reveling in the joy of being a new mother, but recently found that the baby’s face was pale, and his appetite was not as good as before, and he always cried. Anna rushed to the hospital with the baby, the doctor found that the baby has anemia. Anna anxiously asked: Why is the baby so small anemic? Does anemia have an effect on future health? How to detect and avoid anemia early? The doctor did a physical examination of the baby while carefully asking about Anna’s pregnancy and the feeding of the baby after birth, and let the baby have a routine blood test, in response to Anna’s questions the doctor explained one by one. The number of red blood cells per unit volume or the amount of hemoglobin in a person’s blood is significantly lower than normal. Since the number of red blood cells and the amount of hemoglobin in the human body not only varies with age, but also with the living environment, there is no unified international diagnostic standard below 6 months of age, and the standard in China is hemoglobin <145g/L in the neonatal period, <90g/L from 1 to 4 months, and <100g/L from 4 to 6 months is considered anemia. According to the World Health Organization's criteria, hemoglobin <110 g/L in children aged 6 months to 6 years and <120 g/L in children aged 6 to 14 years are judged to be anemic. However, it is worth noting that the hemoglobin should increase by 4% for every 1000 meters of elevation of the place of residence. For example, assuming that Lhasa, Tibet is 3000 meters higher than Shanghai, a 7-year-old Shanghai child with a hemoglobin <120 g/L is anemic, while a child living in Lhasa with a hemoglobin <132 g/L is also anemic. The causes of anemia in children are divided into three main categories, one is insufficient generation: including nutritional anemia caused by deficiencies of hematopoietic substances such as iron, folic acid, VtB12 and hematopoietic dysfunction such as aplastic anemia; the second is excessive destruction: one of them is congenital hereditary anemia caused by intrinsic defects of red blood cells such as hereditary spherocytosis, glucose-6-phosphate dehydrogenase deficiency (also known as serpentine disease) and Thalassemia, the other is non-genetic anemia caused by extrinsic factors of red blood cells such as neonatal hemolytic disease, autoimmune hemolysis, and infectious anemia; the third is blood loss anemia caused by excessive loss such as acute hemorrhage, chronic gastrointestinal inflammation, and parasitic diseases. Most anemia in childhood is caused by malnutrition, the most common is iron deficiency anemia and nutritional megaloblastic anemia (vitamin B12, folic acid deficiency), according to statistics, nearly 40% of school-age children and nursery children in China suffer from varying degrees of anemia. Anna asked in disbelief: malnutrition? Nowadays, children are living in such good conditions, the whole family surrounds a baby, how can there be malnutrition? The doctor explained that insufficient intake of iron, folic acid and VtB12 due to exclusive breastfeeding (low iron content in milk and vegetarian diet of the mother) and failure to add complementary food in time are the main causes of nutritional anemia in children; while prematurity, twins or iron deficiency of the mother during pregnancy can cause congenital iron storage deficiency in the baby's body, coupled with the rapid growth and development of the baby after birth, the need for more, or due to unreasonable food mix, chronic diarrhea, recurrent infections make iron Diarrhea and recurrent infections can cause nutritional anemia due to impaired absorption of iron, Vt12 and folic acid. Anemia is a common symptom in infancy and early childhood, and long-term anemia can affect heart function and intellectual development. Therefore, once parents find that their babies are pale or yellow, have a poor appetite, are easily fatigued, have dry hair, and have reduced resistance, they need to be alert to the presence of anemia, especially if they are unresponsive, have a trembling tongue, and are behind or regressing in their intellectual development (e.g., they can sit or crawl instead), they may be suffering from megaloblastic anemia. Malnutrition is not just caused by eating less, to get out of the nutritional misconceptions, food is not the more expensive the more nutritious, while strongly advocating breastfeeding timely addition of complementary foods, premature babies 2 months after birth iron supplementation, timely treatment of chronic diseases, there should be targeted supplementation of iron, folic acid, vitamin B12, in order to ensure the healthy growth of babies.