Acute gastritis has an acute onset and is often caused by chemicals, physical factors, microbial infections or bacterial toxins. Chemicals include drugs, such as salicylic acid, glucocorticoids, and certain antibiotics; physical factors, such as eating foods that are too cold, too hot, and too coarse, can damage the gastric mucosa and cause inflammation. In addition, eating food contaminated with bacteria can cause gastritis. Acute gastritis manifests as abdominal discomfort, nausea or loss of appetite. If treatment is not complete, the symptoms can recur due to improper diet, and it can turn into chronic inflammation. The differential diagnosis of acute gastritis: 1. Acute corrosive gastritis: a history of taking strong acids (sulfuric acid, hydrochloric acid, nitric acid), strong bases (sodium hydroxide, potassium hydroxide) or Lysol, etc. After taking caused burns in the digestive tract, appearing in the mouth, throat, posterior sternum and epigastric pain, accompanied by painful swallowing, difficulty swallowing, frequent nausea, vomiting. Severe cases can vomit blood, vomit blood-tinged mucosal rotten pieces, may occur deficiency, shock or cause symptoms of esophageal and gastric perforation, oral cavity, throat can appear in contact with the inflammation, congestion, edema, erosion, necrotic mucous membrane exfoliation, ulceration or can see black, white scabs. 2, acute appendicitis: The early stage of the disease can appear epigastric pain, nausea, vomiting, but as the disease progresses, the pain gradually shifts to the right lower abdomen, and there is fixed pressure pain and rebound pain, mostly accompanied by fever, increased white blood cells, neutral white blood cells increased significantly. 3, cholecystitis, cholelithiasis: there are recurrent episodes of abdominal pain, often predominantly in the right upper abdomen, which may radiate to the right shoulder and back. During physical examination, sclera and skin jaundice are noted. The right upper abdomen is painful and positive for Murphy’s sign, or an enlarged gallbladder can be palpated. Blood bilirubin quantification and urine triple bile test are helpful for diagnosis. 4. Other lobar pneumonia, myocardial infarction, etc.: Lobar pneumonia, myocardial infarction, etc. may have varying degrees of abdominal pain, nausea, and vomiting at the initial stage of the disease. If detailed medical history, physical examination and necessary auxiliary examinations are taken, it is not difficult to differentiate.