Smooth and oily stool surface is considered to be related to improper diet, indigestion, gastroenteritis, upper gastrointestinal bleeding, etc. 1. Improper diet: when the diet is too greasy, grease can cause the gastrointestinal tract peristalsis abnormally fast, it is difficult to fully digest and absorb the food, which will cause the stool to appear smooth and shiny. At this time, attention should be paid to a light diet. 2. Dyspepsia and gastroenteritis: If there is dyspepsia and gastroenteritis, it will also cause smooth and shiny stools. Antibiotics (such as norfloxacin) and drugs to promote digestion (such as gastrointestinal tablets) can be taken. 3. Upper gastrointestinal bleeding: peptic ulcer, gastritis, etc. can cause upper gastrointestinal bleeding, this time the stool will appear black tar-like, can be treated for the cause of bleeding. The smooth and oily surface of the stool may also be related to other reasons, it is recommended to consult a doctor in time to identify the cause, and under the guidance of the doctor regular treatment.