Pain on the left side of the abdomen is mainly considered for 5 reasons. 1, injury, mostly seen in trauma to the spleen and pancreas caused by fall from height injuries, car accident injuries, especially trauma to the tail of the pancreas, can present with pain on the left side of the abdomen. 2, inflammatory diseases, such as acute pancreatitis, acute gastritis, acute colitis, in addition to manifesting as pain on the left side of the abdomen, there are characteristics associated with their respective diseases. 3, obstructive diseases, commonly jejunal obstruction, left The left side of the abdomen is often characterized by nausea and vomiting in addition to left-sided abdominal pain. 4. tumors, such as colonic splenic flexure tumors, gastrointestinal mesenchymal tumors, left kidney cancer, and malignant tumors of the tail of the pancreas all manifest as left-sided abdominal pain. 5. endocrine diseases, such as endocrine tumors of the pancreas, commonly gastrinoma and pancreatic hyperglycemia, etc.