When a 4-month-old baby has diarrhea: 1, parents should pay attention to feeding light food, to eat less and more meals, if the baby is breast-fed, pay attention to the need for strict sterilization of milk utensils. 2, to pay attention to is to keep warm, especially the abdomen warm. 3, parents can give the baby appropriate oral probiotic treatment, commonly used in the treatment of baby diarrhea probiotic is Bacillus subtilis diphtheriae particles, the specific dosage needs to The specific dosage needs to consult the detailed drug instructions or consult the pediatrician. If the number of diarrhea is more, you can also temporarily add montelukast treatment, montelukast is a gastrointestinal mucosa protector, with a certain antidiarrheal effect, but the drug should not be used for a long time to avoid constipation and other adverse reactions. 4, if the diarrhea symptoms are not relieved after taking the above drugs, parents need to take their babies to the hospital, with the pediatrician to give examination and treatment, check the stool routine plus The stool routine plus rotavirus, blood routine, etc. to help understand what type of infection exists, if it is a bacterial infection or viral infection, the corresponding medication needs to be given.