Solid bodily waste discharged from the colon through the anus during defecation. Normal feces are 75% water. The rest is about 30% dead bacteria, 30% indigestible food matter, 10–20% cholesterol and other fats, 10–20% inorganic substances, and 2–3% protein. The colour and odour are produced by bacterial action on chemical constituents. Many disorders produce abnormalities in the feces, usually constipation or diarrhea. Bleeding in the stomach or intestines may show up as dark red to black stools. Tests are needed to detect small amounts (occult blood). High fat content usually indicates disease of the pancreas or small intestine. Many diseases are spread by contamination of food with feces of infected persons.