Four-month-old babies with mucus in the stool may be related to indigestion, lactose intolerance, acute enteritis, etc., the treatment is based on medication, usually strengthen the baby’s care. 1. indigestion: if the baby eats too much, it is easy to cause indigestion, the symptoms of mucus in the stool, you can give the baby the use of probiotics such as bacillus subtilis bacillus granules and other adjustments to improve the mucus in the stool symptoms. 2. Lactose intolerance: four-month-old babies may not have enough lactase enzyme in their bodies to completely break down lactose, which can cause mucus in the stool, you can give your baby oral lactase before eating milk. 3. Acute enteritis: if the diet is not clean, intestinal bacterial infections, infringement of the intestinal mucosa, causing mucus in the stool, according to the drug allergy to choose the application of antibacterial drugs such as cefixime. At the same time oral probiotics such as bacillus subtilis dictyostelium granules and so on to regulate. It is recommended that four-month-old babies with mucus in the stool should go to the hospital in time for examination and treatment with medication under the guidance of the doctor. The above drugs need to be used in accordance with medical advice.