The main causes of left lower abdominal pain in men can be summarized as follows: 1, prostatic hyperplasia, prostatic hyperplasia is the most common disease in middle-aged and elderly men, the main cause is due to the imbalance of hormones in the body after middle age, long-term prostatic hyperplasia can lead to frequent urination, painful urination, urinary waiting, and can also cause pulling pain in the left lower abdomen; 2, left ureteral obstruction, the most common cause is left The most common cause of left ureteral obstruction is left ureteral stone, patients can have less urine and swelling pain in the left lower abdomen; 3, inflammation of the left ureter can also lead to pain in the left lower abdomen; 4, severe varicose veins in the left testicular veins can lead to a feeling of swelling in the left lower abdomen; 5, ulcerative colitis and acute toxic dysentery patients can have diarrhea, urgency and pain in the left lower abdomen and other symptoms.