Diarrhea with oil in the stool is considered to be related to indigestion, acute gastroenteritis, ulcerative colitis, pancreatitis and so on. 1. Indigestion: Indigestion can cause diarrhea and oil in stools in some patients, and it is easy to be accompanied by postprandial fullness, burning sensation in the middle and upper abdomen and other symptoms. Dyspepsia is mainly related to decreased gastric tolerance to food diastolic function, gastrointestinal dysfunction and so on. 2. Acute gastroenteritis: Acute gastroenteritis is related to pathogenic microbial infections and intake of irritating foods. Typical symptoms include diarrhea, abdominal pain, nausea and vomiting, fever, etc. Some patients may have oil in the stool due to abnormal secretion of digestive juices caused by the disease. 3. Ulcerative colitis: the cause of the disease is not clear, may be the environment, genetic, intestinal flora dysbiosis and other factors play a role in each other. Patients will have diarrhea with mucus, pus and blood stools, abdominal pain, abdominal distension, loss of appetite, nausea and vomiting. Some patients can be due to intestinal mucosal surface lesions, enzyme defects, etc., affecting the normal absorption of fat, thus causing defecation with oil. 4. Pancreatitis: Pancreatitis patients can be due to pancreatic lipase secretion or lack of, resulting in intestinal fat digestion and absorption, thus manifested in the bowel with oil. The occurrence of pancreatitis may be related to long-term alcohol consumption, biliary obstruction and other factors, patients are often accompanied by acute abdominal pain, nausea and vomiting, fever and other symptoms. There are many causes of diarrhea with oil in stool, such as celiac disease, pancreatic cancer, limited ileitis, intestinal fistula. It is recommended that people with diarrhea and oil in their stools seek medical attention in order to clarify the disease and follow the doctor’s instructions for treatment.