Below the navel is always distended but not painful means bloating, may be due to intestinal dysfunction, intestinal obstruction, abdominal ascites and other diseases. 1. Intestinal dysfunction: Intestinal dysfunction can cause slow peristalsis, resulting in the accumulation of food in the intestinal tract to produce a large amount of gas, which can easily cause abdominal distension symptoms, some patients will also be accompanied by nausea and vomiting, loss of appetite. 2. Intestinal obstruction: Intestinal obstruction is a disease caused by the abnormal passage of intestinal contents due to intestinal lesions, and patients will suffer from constipation, vomiting, abdominal distension and so on. Patients may experience constipation, vomiting, abdominal distension, etc. When the symptoms are severe, they may also suffer from abdominal pain. 3. Abdominal ascites: abdominal ascites refers to the fluid in the abdominal cavity exceeds 200 milliliters, and this disease will cause patients to have difficulty breathing, abdominal enlargement, abdominal distension, fever and other conditions. Patients should go to the hospital for examination and treatment when small abdominal distension occurs.