Causes of mucus in the stool include dehydration, constipation and gastrointestinal inflammatory conditions, such as irritable bowel syndrome, Crohn's disease and rectal ulcers, states Healthline. Conditions such as diverticular disease, anal fissure, peptic ulcers and gastroenteritis can cause blood in the stool, notes WebMD.
An inflammatory process can break down the intestinal mucus layer that protects the body from food residual and pathogens in the intestines, causing excretion of mucus in the stool, reports Healthline. Symptoms include abdominal pain, bloating and blood in the stool.
Projection of pouches from the colon; a tear or cut in the tissue lining the anus; a viral or bacterial infection in the stomach, such as gastroenteritis; and inflammation of the colon can cause blood in the stool, explains WebMD.