Three-month-olds with green stools are associated with underdevelopment of the digestive system, diet of breastfeeding mothers, diet of infants, and inflammation of the stomach and intestines, and it is recommended to consult a professional doctor for treatment. Common causes 1, digestive system underdevelopment: due to the underdevelopment of the digestive system, bile is excreted with the feces, and bilirubin in the bile is turned into bilirubin by the intestinal reaction, resulting in green stools; 2, breastfeeding mother’s diet: mothers take iron supplements or consume too much spicy and greasy food, which will cause children to have green stools; 3, infant diet: milk powder contains more mineral components, such as iron, or infants are lactose intolerant and cannot digest it completely, resulting in green stools; 4, infant diet: the infant is lactose intolerant and cannot digest it completely, resulting in green stools; 4, infant diet: the infant is lactose intolerant and cannot digest it completely, resulting in green stools. Tolerance, can not be fully digested, resulting in green stool; 4, gastrointestinal inflammation: a small number of infants due to staphylococcus aureus infection caused by enteritis, intestinal peristalsis increased, biliverdin is not fully responded to, which can lead to green stool. Treatment: Take lactobacillin tablets as prescribed by the doctor to regulate intestinal flora. Bacterial infection, can follow the doctor’s instructions to use cefixime for anti-infection treatment. Precautions 1, it is recommended that mothers eat more vegetables, fruits, avoid cold, spicy, stimulating food; 2, pay attention to feeding hygiene, hot water soak the bottle and then wash; 3, pay attention to warmth, to prevent cold; 4, gently knead the baby’s abdomen to promote gastrointestinal digestion.