Physiological diarrhea is usually common in breastfed infants, mostly occurring up to 6 months of age. Diarrhea does not appear immediately after birth. The reason for this is that the diarrhea is caused by a nutrient contained in breast milk, such as protein or fat, that exceeds the needs of the infant and exceeds the infant’s digestive and absorption capabilities, which are well developed. Physiological diarrhea often has these characteristics: 1. The number of stools varies from 2-3 to 8-9 times a day, like paste, without special odor. If the stool is more sticky, more breast milk contains more protein than the infant’s digestive and absorption function, such as thin stool, more breast milk contains more sugar than the infant’s absorption function, such as stool contains oil drops, more breast milk fat content is higher. Some times breast milk is higher in both protein and fat. 2, the child is a bit fat, face, behind the ears or hairline often have milk ringworm. 3, The child’s body still absorbs more nutrients than the average child, despite some diarrhea. Therefore, these children continue to gain weight while having diarrhea, and their weight is heavier than other babies of the same age, and their growth and development are not affected, and they have a good appetite and do not get sick. Physiological diarrhea does not require weaning or anti-diarrheal medication. The mother’s diet can be adjusted slightly, for example, she should not eat too greasy or too high protein. Babies can add complementary foods a little earlier. As the baby grows up, the digestive function is enhanced, the proportion of breast milk to food decreases, and supplementary foods such as porridge, noodles, fish and puree are gradually added, so the child’s stools will slowly become normal.