What causes diarrhea in a 4-month-old baby?

Diarrhea in a 4-month-old baby is commonly caused by gastrointestinal infections, which may be triggered by viruses, bacteria, or parasites. Gastrointestinal infections are usually accompanied by symptoms such as diarrhea, vomiting, and fever. Improper feeding can also lead to diarrhea in babies, such as feeding too much, too quickly, or overfeeding. Since a baby's gastrointestinal and digestive functions are not yet fully developed, they are more prone to gastrointestinal discomfort and diarrhea.