1. Symptoms of vomiting and diarrhea in babies Vomiting and diarrhea in babies is a common disease in infants and young children, and its main symptoms are persistent vomiting and diarrhea. Generally speaking, the baby\’s vomited material is stomach contents, which are lighter in color, sometimes with yellow or green liquid. Diarrhea is characterized by increased stool frequency, small amount, thin quality, lighter color, and sometimes even watery stools.