The main symptoms of left hemicolectasis are: 1. abdominal pain. The symptoms are atypical in mild cases, but severe ones are pain and discomfort in the left lower abdomen, sometimes even radiating to the whole abdomen, which can be relieved after defecation. 2. diarrhea, mostly mucus stools or pus and blood stools, about three or four times a day, more than ten or even tens of times, can be watery stools. 3. urgency. The first time the person is in a position to do so, he or she will be able to do it again. 4, blood in the stool. After a long time of inflammation, it causes damage to the blood vessels in the inner wall of the intestinal mucosa and bleeding occurs. 5. Other symptoms. Some patients may have insomnia and dreaminess, neurological weakness, abdominal distension, weight loss and weakness, fear of cold, and in severe cases, disorders of water-electrolyte metabolism and malnutrition.