Stools that look like they have oil in them are the result of pancreatitis, dysentery, and upper gastrointestinal bleeding. Stool is formed by the accumulation of food residue and should not contain anything like oil under normal circumstances. The pancreas is able to secrete pancreatic juice to facilitate the digestion of fatty foods, and once pancreatitis strikes, it can cause the secretion of pancreatic juice to be affected. Once pancreatitis strikes, the secretion of pancreatic fluid will be affected. When fatty foods are not neutralized by pancreatic fluid, they will not be absorbed by the intestines and will be excreted directly. Patients with pancreatitis will have steatorrhea, so the stool that comes out will have something like oil in it. Dysentery is caused by bacterial infection. During a dysentery attack, the mucous membrane of the intestine is stimulated by bacteria and becomes necrotic and is excreted along with the stool, resulting in the presence of something like oil in the stool. When upper gastrointestinal bleeding occurs, the blood is oxidized to iron sulfide as it passes through the digestive system. Since iron sulfide is irritating, it causes a large amount of mucus to be secreted from the intestinal wall. These people have shiny stools, mainly tarry stools, and also have abdominal pain, diarrhea, and bloating.