Generally speaking, it is best to add complementary foods when infants and young children are 6 months old, but due to the different developmental conditions of infants and young children, there are individual differences in how many months it is good to add complementary foods, and it is recommended that the earliest is not earlier than 4 months, and the latest is not later than 8 months. Before 4 months due to the immaturity of the gastrointestinal tract, if you add complementary foods too early, it is easy to cause indigestion, resulting in bloating, diarrhea and other symptoms. With the development of infants and young children, the need for nutrition will increase, if you add complementary foods too late, a single breast milk or milk powder in the nutrients can not meet the needs of the child, there may be developmental delays or malnutrition phenomenon. It is generally recommended that infants and toddlers can gradually add complementary foods when they are 4-6 months old, such as egg yolks, rice soup, rice paste or fruit juice, etc., and when they are 7-8 months old, they can gradually add pureed vegetables, pureed fruits, soft noodles, rice porridge, as well as egg yolks, pureed fish, pureed meat and other foods. Infants and young children to add complementary foods need to be added one by one, step by step, can not add a variety of one time, to prevent the addition of too many complementary foods lead to gastrointestinal indigestion of the baby, add complementary foods after the symptoms of indigestion, the need to pause complementary foods, to be adjusted to normal and then continue to feed complementary foods.