Once a day stool left lower abdomen hidden pain is not normal, may be ulcerative colitis, enteritis, irritable bowel syndrome, etc., need to consult the doctor in time. 1. Ulcerative colitis: mostly mild to moderate vague pain in the left lower abdomen or lower abdomen, diarrhea can occur, mildly less than 4 times, and its typical symptom is mucus, pus and blood stool. 2. Enteritis: when bacteria and other pathogens infect the intestinal tract, it can lead to vague pain in the left lower abdomen. 3. Irritable bowel syndrome: abdominal pain can occur after eating, mostly relieved after defecation, and the degree of abdominal pain is usually mild. It is recommended that the person who has a pain in the lower left abdomen once a day go to the hospital in time to clarify the cause of the disease, and standardized treatment under the guidance of the doctor, so as not to delay the condition.