The duration of diarrhea depends on the child's condition, whether it is physiological or pathological diarrhea. For physiological diarrhea in children, which is mostly due to dietary reasons, adjusting the structure of the diet can usually bring improvement. However, physiological diarrhea is not easy to resolve and can sometimes persist for months. If it is pathological diarrhea, it is necessary to identify whether it is caused by bacteria, viruses, or other specific diseases. In such cases, the first step is to perform a stool test on the infant. This involves collecting the child's stool in a clean container and bringing it to the hospital for examination within an hour to determine the cause, which will then guide further targeted medication adjustments. The duration of the illness will depend on the type of pathogen infecting the child.