Four-month-old babies have more causes of diarrhea, such as acute gastroenteritis, lactose intolerance, abdominal cold, etc., and can be treated by general treatment, medication and other methods to stop diarrhea. 1. Acute gastroenteritis: four-month-old babies accidentally infected by viruses or bacteria can cause acute inflammation of the mucosa of the gastrointestinal tract, which can lead to diarrhea, vomiting and other uncomfortable symptoms. (1) general treatment: for small babies acute gastroenteritis emphasizes the continuation of diet, generally no need to abstain from food, you can continue breastfeeding or artificial feeding. (2) medication: for children with severe diarrhea, oral rehydration salts can be given to prevent dehydration; probiotics such as bifidobacteria and lactobacillus can also be given to restore the normal intestinal flora structure; mucosal protectants such as montelukast can also be given to stop diarrhea. Bacterial infections can also be treated with oral antibacterial drugs such as cefixime. 2. Lactose intolerance: The reason why some infants have diarrhea is considered to be caused by lactose intolerance. In this case, you can temporarily stop breastfeeding, give the baby some lactose-free milk powder, can effectively reduce the symptoms of diarrhea. 3. Abdominal cold: babies do not pay attention to warmth when sleeping, can lead to abdominal cold, thus causing diarrhea. This kind of diarrhea symptoms are generally relatively mild, as long as the timely warm work, let the baby drink more hot water and rest can return to normal. It is recommended that the four-month-old baby diarrhea timely medical attention. The above medication should be used in accordance with medical advice.