Small air-fluid plane in the mid-abdomen suggests that there may be intestinal obstruction, acute gastroenteritis and other diseases. 1. Intestinal obstruction: patients with intestinal obstruction may have fluid and gas accumulation in the intestinal lumen, and the intestinal tube may be inflated and dilated, so that the wide and narrow, uneven gas-liquid planes will appear in the abdominal X-ray examination. 2. Acute gastroenteritis: small air-fluid planes in the mid-abdomen can be seen in patients with acute gastroenteritis, abdominal X-ray can show that the intestinal tube is generally not dilated, the air-fluid planes are scattered, numerous, short, and so on, and the air-fluid planes can be dislocated or disappeared after massaging the abdomen. It is recommended to go to the hospital when there are small air-fluid planes in the mid-abdomen, and ask the doctor to make a judgment and clarify the cause of the disease.