If a three-month-old baby or a three-year-old baby shows symptoms of vomiting and diarrhea, it is mostly considered to be acute gastroenteritis, mostly caused by unclean diet or improper diet or cold in the abdomen. Parents are advised to take their babies to the hospital immediately and cooperate with the pediatrician to do relevant tests, such as blood routine, blood biochemistry, stool routine, rotavirus, etc., and give specific medication according to the results of the tests. The pediatrician may give probiotics, combined with antiemetic drugs, and if the infection is serious, may also need to give temporary antibiotics to control the infection. It is important to give your baby a light diet and to eat smaller and more frequent meals. Depending on the symptoms of vomiting, intravenous rehydration therapy can be given if necessary, and attention should be paid to keeping the abdomen warm.