There are very many manifestations of non-absorption of baby formula, the most intuitive is that the baby does not absorb the formula, does not gain weight and does not grow in height. The child’s weight is lower than the normal average weight of children of the same age, which is one of the most intuitive manifestations. There are also other signs of formula intolerance, including vomiting, changes in stool characteristics, including mucus, milk petals, blood in the stool, and even increased stool frequency. Another easily overlooked symptom is that the child may have food intolerance and may experience bouts of crying at night, i.e. night crying. This condition may also be caused by food allergy or food intolerance, which should be emphasized clinically, including in daily life. In this case, including the process of adding complementary foods, the patient may suffer from complementary food intolerance, including vomiting, lack of weight gain, changes in stool characteristics, an increase in nighttime crying, and even rashes and allergies, which may be a result of intolerance or maladaptation. The order and timing of adding complementary foods as well as the frequency and amount should be adjusted appropriately, and the addition of foods should be delayed for a little while. Don’t add too much at the beginning, and keep adding food for a relatively long period of time, maybe more than two weeks. If there is a persistent intolerance, allergen testing should be done in the hospital to see if there are any food allergies, and then supplemental foods should be added under the guidance of a clinical specialist.