If the 4-month-old baby pulls rare mucus, if the baby is in good spirits, responds and eats milk well, without fever, vomiting, abnormal crying and other symptoms, you can observe at home. If the baby’s perianal skin is flushed at the same time as the diarrhea, the stool may be abnormal, because when the stool is abnormal, it will stimulate the skin around the anus, resulting in flushing, or even vesiculation, and you should bring a stool sample to the hospital in time for laboratory tests. If fat globulin particles are present, there is indigestion, and you can take oral digestive aids, such as polypeptide tablets and Clostridium Typhimurium Live Bacteria Bulk. If there are white blood cells, there is an intestinal infection, which can be treated with oral cefixime granules and digestive aids. If there are white blood cells, pus cells and red blood cells in the stool, take the baby to the hospital in time, and if necessary, carry out infusion treatment.