1. Bacterial infection causes diarrhea in infants. Bacterial infection is one of the main causes of diarrhea in infants. Common bacteria include E. coli, salmonella, campylobacter, etc. These bacteria can enter your baby\’s intestines, multiply and release toxins, causing symptoms of diarrhea. Bacterial infections are usually spread through food or water, so parents should pay attention to dietary hygiene and personal hygiene. 2. Viral infection causes infant diarrhea. In addition to bacterial infection, viral infection is also one of the causes of infant diarrhea. Common viruses include rotavirus, norovirus, etc. These viruses will enter the baby\’s intestines and damage the intestinal mucosa, causing diarrhea and vomiting and other discomforts.