The hollowing out of the center of the stomach is generally a normal physiological feature, but it may also be due to abdominal fluid accumulation, ovarian cysts and other diseases. 1. Abdominal fluid: there is a small amount of fluid in the body, which can promote gastrointestinal peristalsis, but if there is an increase in the amount of fluid in the abdominal cavity, it may lead to the accumulation of fluid in the abdomen, resulting in the phenomenon of the two sides of the tummy hollowing out in the middle. It is recommended that patients seek medical examination and treatment of primary diseases in a timely manner. 2. Ovarian cysts: Usually due to infection, environment, diet and other factors, follicular fluid is retained, thus forming cysts. If left untreated, the cysts may become bigger, resulting in the phenomenon of the stomach being concave on both sides and protruding in the middle. Patients can be treated with surgical methods such as ovarian cystectomy under the guidance of a doctor. In addition to physiological factors, patients are advised to consult a doctor in time for examination if they have a stomach bulge in the middle.