There are some common causes of left lower abdominal pain as follows: firstly, it is spasmodic intestinal pain caused by acute enteritis, often accompanied by diarrhea, nausea and vomiting; secondly, it is renal colic caused by urinary stones; thirdly, it is pain caused by pelvic inflammatory disease in women or prostatitis in men; fourthly, it is especially important to exclude pain caused by torsion of ovarian cysts in women; fifthly, it is pain caused by ectopic pregnancy in women, and pain caused by rupture of the corpus luteum and hemorrhage in women.