Blood and mucus in stool may be caused by internal hemorrhoids, ulcerative colitis, intestinal tumors and other reasons. 1. Internal hemorrhoids: under the friction stimulation of dry stool, it may lead to bleeding of internal hemorrhoids, while dry stool will also stimulate the intestinal mucus to increase, and the situation of blood and mucus in the stool. 2. Ulcerative colitis: abnormal immune function leads to intestinal mucosal damage, which will stimulate the intestinal tract, and there will be blood and mucus in the stool. 3. Intestinal tumor: the growth of intestinal tumor invades blood vessels or breaks down, which will lead to blood in stool. At the same time, the tumor will stimulate the intestinal mucus to increase, so there will be blood and mucus in the stool. There may be other reasons for blood and mucus in the stool, it is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy under the guidance of the doctor.