The middle of chest includes stomach, lower esophagus, and left outer lobe of liver, so when pain occurs in the subxiphoid process and upper abdomen, the possibility of gastric diseases is very high, which may be gastritis, gastric ulcer, or gastric cancer, and needs to be further clarified by gastroscopy. If gastroscopy finds inflammation in the mucosa of gastric cavity, it suggests gastritis; if ulcer foci can be found, it suggests gastric ulcer; if there is a mass, or sunken foci with elevation around it, it generally suggests gastric cancer; after suspecting gastric cancer, it is necessary to take out a small amount of tissues to do pathological examination; if cancer cells can be found in the pathological examination, it will be confirmed to be gastric cancer, and it will be necessary to carry out radical surgery for gastric cancer after the diagnosis of gastritis and gastric ulcer, and it will be necessary to carry out radical surgery for gastric cancer after the diagnosis of gastritis and gastric ulcer. Gastritis and gastric ulcer can be treated conservatively by internal medicine.