Thickening of the wall of the descending colon with little exudation around it may be caused by ulcerative colitis, Crohn’s disease, colon cancer and other diseases. 1. Ulcerative colitis: the cause of ulcerative colitis may be related to immune factors, genetic factors, intestinal microbiological state and other reasons. Patients will have diarrhea, abdominal pain and other symptoms, and mucus may also appear in the rectum or colon. 2. Crohn’s disease: the cause of Crohn’s disease is not clear, may be related to environmental factors, genetic factors, infectious factors, immune factors and other reasons. Patients will have fever, malnutrition, anemia, thickening of the intestinal wall, mucus and bloody stools in the colon and other symptoms. 3. Colon cancer: the causes of colon cancer are relatively complicated, which may be related to environment, living habits, diet and genetic factors, etc. Patients may suffer from weight loss, emaciation, narrowing of intestinal lumen due to thickening of intestinal wall, and blood in stool. If there is a small amount of exudation around the thickened wall of the descending colon, it is recommended to go to the emergency room of a regular hospital for examination and clarification of the cause of the disease.