4 major causes of acute gastritis: the etiology is diverse, including acute stress, drugs, ischemia, bile reflux and infection. 1, acute infections and pathogenic toxins: certain bacteria, viruses, and even parasites, or their toxins can cause acute inflammation of the gastric mucosa, most of which have been categorized as infectious diseases. Acute cellulitis or acute suppurative gastritis (acutephlegmonousgastritis), which can also involve the gastric mucosa, is a suppurative disease caused by bacterial infection of the gastric lining, often occurring in immunodeficient patients. The disease is serious, but has become extremely rare since the widespread use of antibiotics. The most common causative organisms are Streptococcus a, Staphylococcus or Escherichia coli. Septic inflammation often originates in the submucosa and can lead to necrosis and detachment of the mucosa, or even extend to necrosis of the gastric wall, perforation and peritonitis. Systemic weakness, malnutrition, infections, gastric surgery and even gastric polypectomy are causative factors. Helicobacter pylori (Hp) infection can also cause acute gastritis. 2, physical and chemical factors chemicals: especially drugs caused by gastric mucosal inflammation is common, which most often cause gastritis drugs are non-steroidal anti-inflammatory drugs (non-steroidal anti-inflammatory drug (non-steroidal anti-inflammatory drug)) such as aspirin, indomethacin (anti-inflammatory pain) and so on. The mechanism may be to inhibit cyclooxygenase activity, impede prostaglandin synthesis, and weaken the protective effect on the gastric mucosa, and these drugs can cause superficial mucosal injury and submucosal hemorrhage. In addition to the stomach, it is also seen in the duodenal bulb. Other drugs such as ethanol, iron, potassium chloride oral solution, antitumor drugs and antibiotics can stimulate the mucosa and cause superficial injury. Ethanol system due to its lipophilic and lipolytic properties, disrupting the mucosal barrier. It causes epithelial cell damage, intramucosal hemorrhage and edema. Bile reflux gastritis can be characterized as an endogenous chemical inflammation. It is commonly seen after Billroth II gastrectomy. Bile salts, phospholipase A, and other pancreatic enzymes in bile and pancreatic fluid can damage the residual gastric mucosa and produce multiple erosions. Indwelling gastric tube, foreign body in the stomach, and after radiotherapy for pancreatic cancer can cause physical gastric mucosal damage, leading to inflammation. 3, stress acute stress: can be caused by severe organ disease, major surgery, extensive burns, shock or intracranial lesions, and even psychosomatic factors. Although the exact mechanism has not been fully understood, it is believed that gastric mucosal ischemia and H+ back diffusion into the mucosa as the main pathogenetic factors, and in some cases, there is also a reflux of bile into the stomach and pancreatic fluid involved. Under the above severe conditions, the physiological compensatory function of stress is insufficient to maintain the normal operation of gastric mucosal microcirculation, resulting in relative hypoxia of the mucosa, decreased mucus secretion, and insufficient local prostaglandin synthesis, leading to the destruction of the mucosal barrier and the back-diffusion of H+, and the decrease of mucosal pH, which further damages the blood vessels and the mucosa, and causes erosions and hemorrhages. Acute stress can strongly stimulate platelet-activating factor activity, leading to strong vasoconstriction. Lesions are most commonly seen in the proximal stomach, but can also occur in other parts of the stomach. Blood seepage in the gastric lumen is common, about 20% of the larger amount of bleeding occurs, a small number of acute ulcers can occur, burns caused by the special called curling ulcer, central neuropathy caused by the special called Cushing ulcer. 4, vascular factors are seen in elderly patients with atherosclerosis, or after abdominal artery embolization treatment, is caused by vascular occlusion.