The causes of a big belly may be obesity, pregnancy, lumps and so on. 1. Obesity: usually patients with a big belly and long-term non-exercise subcutaneous fat metabolism disorders lead to fat accumulation in the abdomen obviously, so patients should exercise regularly to eliminate fat accumulation, and pay attention to dietary adjustments. 2. Pregnancy: If patients of childbearing age appear to stop menstruation, and accompanied by a gradual increase in the size of the abdomen, it may be pregnant. If necessary, you can go to the hospital for relevant examinations, and should not abuse drugs, so as not to affect the health of the fetus. 3. Lumps: a large belly may also be caused by lumps, patients can go to the hospital to check whether it is a benign lump or a malignant tumor. Common benign lumps include ovarian cysts, small bowel tumors, etc. Malignant tumors include endometrial cancer and colon cancer. There are many other reasons for a big small stomach, such as urinary retention, bladder tumors, pelvic fluid accumulation, post-partum abdominal wall laxity, etc. It is recommended that patients actively seek medical attention to clarify the cause of the disease and then carry out the relevant treatment.