Female patients with left-sided lower abdominal distension and pain can be caused by the following diseases: first, tumors of the sigmoid colon and rectum, with the evolution of the disease, there will be incomplete obstruction of the intestinal cavity, the patient will have difficulty in defecation or unformed bowel movements, there will also be obvious symptoms of distension and pain in the lower abdomen, there will also be anemia, the cause of the occurrence is related to the polyp malignancy, after the diagnosis should choose early surgery. Second, gynecological diseases, commonly left adnexitis or ovarian cysts, the patient will also have fever or abdominal masses, accompanied by abdominal pain, examination in the left lower abdomen can also be palpable regular marginal masses, accompanied by slight tenderness, ultrasonography can confirm the diagnosis, if necessary, you need to choose surgery to remove the lesion, for simple inflammation, you can choose the anti-infection treatment method. Third, patients with gastroenteritis and intestinal spasm may also have lower abdominal pain, and in severe cases, diarrhea with nausea and vomiting may also occur.