If you have vague swelling under the left rib cage, you should suspect spleen or pancreatic diseases according to the anatomical location. You need to improve the relevant examinations, including ultrasound or CT of the digestive system, mainly to check the liver, bile, spleen and pancreas to see if the spleen is enlarged. In addition, some patients with pancreatitis may also have vague swelling under the left rib cage. In addition to ultrasound or CT of the digestive system, serum and urine amylase measurements should be done. Once the diagnosis of pancreatitis is confirmed, the patient should be instructed to fast from water, to decompress the gastrointestinal tract if necessary, and to take acid suppression and inhibition of pancreatic enzyme secretion, using omeprazole or growth inhibitors. In addition, some gastrointestinal diseases may also manifest as vague swelling under the left rib cage, and a gastrointestinal ultrasound or gastroscopy can be done to clarify the diagnosis.