A 2-month-old baby’s diarrhea may be caused by lactose intolerance, underdeveloped digestive system, gastrointestinal tract infection and other problems. 1. Lactose intolerance: If your baby is lactose intolerant, he or she may have diarrhea. This is due to the baby’s inability to absorb and digest the lactose in breast milk, resulting in diarrhea, which may be accompanied by nausea, vomiting, bloating and other symptoms. 2. Imperfect development of the digestive system: 2-month-old babies are likely to be due to the digestive system is not fully developed, which leads to weak digestive ability, if eating too much will lead to the intestinal tract can not be properly digested, resulting in diarrhea. 3. Gastrointestinal infections: If the baby is infected with bacteria or viruses, it can also lead to diarrhea, and may also be accompanied by nausea, vomiting, blood and other symptoms, parents should go to the regular hospital in a timely manner to confirm the diagnosis. 2-month-old baby diarrhea, there may also be other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.