Intolerance to a fatty diet is one of the conditions of postcholecystectomy syndrome (PCS), which is a collective term for abdominal symptoms such as abdominal pain and dyspepsia that occur after surgery in patients with a history of cholecystectomy. These symptoms are nonspecific and vary according to the underlying etiology, but often include pain in the right upper abdomen or epigastrium, mostly after meals, with sharp pain. So, how should a patient be diagnosed who is intolerant to a multi-fat diet? Here is a brief description: Half of the PCS patients have abdominal pain or “dyspepsia” (feeling of fullness in the upper or right upper abdomen, abdominal rumbling, nausea, vomiting, constipation, fat intolerance, or diarrhea) within a few weeks after surgery, and the other half have symptoms for months or years after surgery. These symptoms are nonspecific and vary depending on the underlying etiology, but often include pain in the right upper abdomen or epigastrium, most often after meals, which is sharp. Other symptoms may include heartburn, belching, vomiting and intolerance to a fatty diet. A small number of patients may have severe cholecystitis or pancreatitis with severe pain and may be accompanied by fever, jaundice or vomiting. Examination of these patients often reveals a definite disease more easily than those with mild or no specific symptoms. Physical examination often has no special value except for the obvious jaundice that can be detected. I. Diagnosis: 1. Clinical manifestations. 2, laboratory and other ancillary tests. Exclusion criteria: 1. Not consistent with organic brain disorders, somatic diseases and psychotic disorders due to psychoactive substances and nondependent substances; 2. Some schizophrenic symptoms may exist, but they do not meet the diagnostic criteria for schizophrenia. If the diagnostic criteria for symptoms of schizophrenia are also met, the differential diagnosis can refer to the diagnostic criteria for schizo-affective psychosis.