Acute gastroenteritis can be diagnosed by physical examination, routine blood tests, and routine stool tests. The details are as follows: 1. Physical examination: when patients with acute gastroenteritis are physically examined, there will be obvious pressure pain near the navel when squeezed. Intestinal peristalsis is accelerated, and the patient’s bowel sounds are active and greater than 6 times per minute. 2. routine blood test: in acute gastroenteritis patients in the attack period, routine blood test, white blood cells and neutrophils will be significantly higher. 3. Stool routine examination: If the patient’s stool examination suggests that the white blood cells are obviously high. In addition, stool routine examination can also clarify whether the patient is bacterial infection or viral infection. In conclusion, when acute gastroenteritis occurs, it is recommended to go to the hospital in time for examination, to clarify the causative factors, and symptomatic treatment.