Breastfeeding diarrhea is mostly seen in infants less than 6 months of age and is also known as physiological diarrhea. Soon after birth, diarrhea, no symptoms other than an increase in the number of bowel movements. 1, the causes of breast milk diarrhea: (1), high prostaglandin content in breast milk, prostaglandin can promote the smooth muscle movement of the small intestine, increase the secretion of water and electrolytes and produce thin stools. (2), children are intolerant to lactose and lack of lactase in the body. (3), the digestive system and digestive enzymes of children are not yet fully developed. 2, breast milk diarrhea treatment measures (1) for breast milk diarrhea such as children with good mental appetite, no vomiting, normal weight gain, does not affect the growth and development of young children, do not need special treatment, and so on the child’s digestive system is fully developed, the gastrointestinal tract to prostaglandins and lactose slowly adapt to the gradual increase in complementary foods will naturally ease. The application of drugs also cannot solve the problem at the root. (2) For children with more serious symptoms, which affect their appetite and spirit and normal growth and development, the fundamental solution is to change milk. Changing to milk or other dairy products will usually work. However, in such cases, care should be taken to identify whether the diarrhea is pathological or not. Breastfeeding diarrhea does not usually affect the child’s spirit and appetite or growth and development. (3) The timely and correct addition of complementary foods after the baby is 4 months old can help relieve breast milk diarrhea. Parents should not worry too much about breast milk diarrhea, as it does not affect the growth and development of the baby and does not need to be treated, as the baby grows and develops, it will gradually improve with the addition of complementary foods.