For mild diarrhea, the primary goal is preventing dehydration, so ensure you are offering plenty of fluids. Introduce 'binding' foods like well-cooked curd rice, bananas, or lassi without added salt and sugar to help firm up the stool. If your baby hasn't been exposed to new foods yet, proceed cautiously and consult your pediatrician regarding any supplements like probiotics, which may help balance their digestive system.