Babies with weak spleens and stomachs often suffer from vomiting and diarrhea due to diet and other reasons. The most common cause is gastroenteritis. Its typical clinical manifestations are diarrhea, nausea, vomiting and abdominal pain. Viral infection is the most common cause of gastroenteritis, and there are a variety of viruses that can cause gastroenteritis, the most common being rotavirus, followed by norovirus, astrovirus and enteric adenovirus. The most important thing in treating gastroenteritis in babies is to replenish water and electrolytes. It is sufficient for the child to stay in bed and drink sufficient amount of water (e.g., oral rehydration salts solution), and even patients who are vomiting should try to drink as much water as possible. Nursing infants should continue to nurse. Carbonated beverages, tea, sports drinks, caffeinated beverages, and fruit juices are not suitable for rehydration. Intravenous rehydration is necessary if the child’s vomiting or diarrhea is prolonged or if there is severe dehydration. Antiemetics may be added for severe vomiting, and antidiarrheals may be added if the diarrhea lasts longer than 24 to 48 hours and there is no indication of a more serious bacterial infection. Antiemetics and antidiarrheals are usually not recommended for children. Because antibiotics may cause diarrhea or promote the growth of drug-resistant bacteria, antibiotics are usually not recommended even if the causative agent of gastroenteritis has been identified. However, antibiotics may be used for certain pathogenic bacteria (e.g., Campylobacter, Shigella, Vibrio cholerae, etc.) infections or if the patient has traveler’s diarrhea. Antibiotics are not effective for gastroenteritis due to viral infections. Gastroenteritis due to parasitic infection requires antiparasitic drugs. Gastroenteritis in children develops rapidly and electrolyte disorders are a very dangerous problem. Self-administration of antiemetic and antidiarrheal medications is generally not recommended in the early stages, and prompt medical attention should be sought.