A small amount of mucus in stool is usually nothing to worry about. Stool normally contains a small amount of mucus — a jelly-like substance that your intestines make to keep the lining of your colon moist and lubricated. But you should talk to your doctor if you notice an increased amount of mucus in stool — particularly if it begins happening regularly or if it's accompanied by bleeding or a change in bowel habits. Mucus in stool can occur with a variety of intestinal infections that cause severe diarrhea. In more serious conditions — Crohn's disease, ulcerative colitis and even cancer — mucus in stool may be bloody or accompanied by abdominal pain.