Elderly people with left lower abdominal pain and vomiting are mainly considered to be related to food poisoning, digestive tract diseases, urinary system diseases and drug effects. 1. Food poisoning: after eating poisonous mushrooms, rotten and spoiled food or food containing more pesticide residues, food poisoning can occur, and its typical symptoms include abdominal pain, diarrhea, vomiting, fever and so on. The typical symptoms include abdominal pain, diarrhea, vomiting, fever, etc. After food poisoning, the patient can have left abdominal pain and vomiting and other symptoms. 2. Gastrointestinal diseases: for example, ulcerative colitis, pancreatitis mainly in the tail of the pancreas, proctitis and other diseases, all of which can cause obvious pain in the left side of the abdomen and vomiting and other uncomfortable symptoms. It is necessary to improve the colonoscopy and abdominal CT and other tests to clarify the cause and location of the disease. 3. Urinary system diseases: such as left ureteral stones, acute pyelonephritis and other diseases, during the acute attack, can also cause such symptoms. It is also accompanied by obvious urinary frequency, urinary pain and abnormal urinalysis. 4. Drug effects: After applying morphine, digitalis and other drugs, abdominal pain, nausea, vomiting, skin rash and other adverse reactions can occur, and should be promptly consulted for medical treatment. The appearance of such symptoms may also be related to other causes. Must pay attention to, as soon as possible to consult a doctor for examination, and be treated accordingly.