Possible causes of small amount of mucus, pus and blood after stool include chronic dysentery, ulcerative colitis, intestinal cancer and other causes. 1. Chronic bacillary dysentery: The occurrence of Shigella intestinalis infection, amoeba and other infections may lead to chronic dysentery, mucus pus and blood in the stool, diarrhea, abdominal pain, fever and other symptoms. 2. Ulcerative colitis: usually accompanied by mucus-pus-blood stools, but the fever is not obvious, only in severe cases, there will be high fever; it may be accompanied by pressure pain in the left lower abdomen; if the disease persists for a long time, it may also lead to anemia, arthritis, erythema nodosum and other complications. 3. Bowel cancer: when colon cancer or rectal cancer occurs, mucous pus and blood stool may appear, or it may be simple blood in stool. It may be accompanied by abdominal pain, anemia, abdominal mass, weight loss, etc. Fever may occur, but cancerous low-grade fever is the main cause. There may be other intestinal diseases such as tuberculous enteritis, etc. It is recommended to go to the hospital in time, complete the examination, make a clear diagnosis, and then follow the doctor’s instructions to treat accordingly, so as to avoid delaying the condition.