The appearance of mucus with blood in the stool may be caused by hemorrhoids, perianal abscess, bacillary dysentery, rectal cancer and other reasons. 1. Hemorrhoids: when hemorrhoids are more serious, it may cause hemorrhoids to prolapse from the anus, because hemorrhoids can not be put back for a long time, which will easily cause necrosis of hemorrhoids tissues, which may cause bleeding and pus at the anus, and when defecating, these pus and blood will easily be stained on stool, which may cause mucus with blood on the exterior of stool. 2. Perianal abscess: due to the presence of infection in the perianal area, when the infection forms a stimulus to the rectum, it is easy to cause mucus secretion. And perianal abscess patients often have constipation, when defecation, due to dry and hard stool, easy to cause abscess breakage, resulting in the appearance of mucus with blood. 3. Bacterial dysentery: this disease is usually caused by bacterial infection of the intestinal tract, which can lead to inflammation or ulceration of the rectum, which may cause mucus with blood on the appearance of stool, and may be accompanied by abdominal pain, diarrhea and other symptoms. 4. Rectal cancer: Most of the early rectal cancers are asymptomatic; when rectal cancer grows to a certain degree, there are changes in bowel habit, bloody stool, pus-blood stool, urgency, constipation, diarrhea, etc.; the stool gradually becomes thin, and in the late stage, there are obstruction of defecation, emaciation and even malignant disease. The appearance of mucus with blood in the stool may appear. The appearance of mucus with blood in the stool may also be caused by other reasons, it is recommended to consult a doctor as soon as possible, and be guided by a doctor for treatment.