Under normal circumstances, defecation cannot excrete oil, if there is a situation of defecation and oil, it indicates that the digestive system has a disease. Under normal circumstances, the fat that enters the body will be hydrolyzed and metabolized by bile, and related digestive enzymes, and absorbed by the body to provide energy for the body’s daily activities, and through metabolism is ultimately discharged from the body in the form of water and carbon dioxide, and the remaining unutilized fat in the body is stored within the fat cells, and is rarely discharged through the bowels. In the case of disease, such as after cholecystectomy, or other gastrointestinal diseases that reduce the secretion of bile, pancreatic juice and other digestive juices, the fat in the food can not be properly digested and absorbed, and it will be excreted from the stools, a condition known as steatorrhea. This condition is known as steatorrhea, which is characterized by a layer of oil floating on the top layer of the stool and can lead to weight loss or even emaciation in the long term. If there is a situation of defecation with a layer of oil floating on the stool, it is recommended to go to the hospital in time, combined with other symptoms as well as imaging tests and other means to clarify the diagnosis of the disease and timely treatment.