Three month old babies with green stools are usually associated with indigestion, improper diet of the mother, lactose intolerance, food allergies, etc. It is recommended that parents take their babies to the pediatric gastroenterology department for routine stool tests to determine the cause. It is recommended that parents take their babies to the pediatric gastroenterology department for routine stool tests to determine the cause of the condition. 1, dietary factors: If the mother breastfeeds and eats too much greasy, it will lead to too much greasy milk, which is difficult for the baby to digest after ingestion and will also appear green stool. Therefore, breastfeeding mothers should pay strict attention to diet, to light, well-digested food, avoid high salt, high fat, high sugar food, so as not to affect the quality of milk, so that the baby has a bad reaction; 2, indigestion: three months old infant physiological function has not been perfect, the gastrointestinal tract digestion and absorption function is weak, if the baby eats too much or abdomen cold, may lead to indigestion, green stool. Parents should adjust the baby’s food intake, or appropriate probiotics to regulate; 3, lactose intolerance, food allergies: baby lactose intolerance or food allergies, may also pull green stool, lactose intolerance is recommended to reduce lactose intake, appropriate consumption of probiotics, lactase, etc.; food allergies to avoid eating such food, if it is allergic to cow’s milk protein can be applied to formula milk feeding. Note parents should pay attention to the abnormal bowel movements of their babies, they can seek medical advice to clarify the cause, pay attention to keeping the abdomen warm, breastfeeding is still recommended for three-month-old babies, the mother’s diet should be light and nutritious.