Patients with acute gastroenteritis can buy montelukast, emmenagogue, probiotics, omeprazole and rehabilitative new liquid from pharmacies. The clinical manifestations of acute gastroenteritis are mostly diarrhea, nausea, abdominal pain and vomiting, which are often caused by unhygienic food or cold or hot stimulation of the stomach and intestines, etc. Intravenous rehydration or oral rehydration salts should be administered. If the condition is more severe in the acute stage, with more frequent bowel movements, accompanied by vomiting or, in severe cases, dehydration and electrolyte disorders, patients should fast from water, rest the gastrointestinal tract completely, and rely on intravenous fluids to replenish water and electrolytes and other treatment modalities. Patients with milder cases can drink sugar saline to replenish water and salt and correct disorders of water and salt metabolism. In terms of oral medication, you can buy antidiarrheal treatment such as montelukast and emmenagogue at pharmacies, regulation of intestinal flora such as probiotics, as well as omeprazole to inhibit stomach acid and antiemetic treatment, and rehabilitation new liquid to protect the gastric mucosa. In addition, you should eat thin rice, drink porridge and drink plenty of water to avoid dehydration caused by diarrhea, because excessive frequent vomiting and defecation will reduce water and electrolytes in body tissues, so you must increase fluid intake, which contains a lot of sugar and electrolytes and can also help reduce diarrhea. After smooth transition of liquid diet, it can be changed to semi-liquid diet with low fat and less residue, but still small amount of meals should be eaten, 5-7 meals per day, the amount of food should not exceed 300mL per meal at the beginning, and later increase the amount one by one, it is better not to eat high fat, high sugar and strongly stimulating food.