1, acute simple gastritis: acute simple gastritis can be caused by chemical substances, physical factors, microbial infection or bacterial toxins. The gastric mucosa lesions are mainly congestion, edema, increased mucus secretion, surface covered with white or yellow exudate, may be accompanied by spot bleeding and mild erosion, the onset of the disease is more acute, mainly manifested as epigastric discomfort, pain, loss of appetite, nausea and vomiting. The disease is often accompanied by acute enteritis with diarrhea and periumbilical pain, and in severe cases, fever, water loss, acidosis, and even shock. The disease has a short course and is self-limiting. The main principles of treatment are to eliminate the causes, symptomatic treatment, rational application of antibiotics and attention to correct water and electrolyte disorders. 2, acute erosive gastritis: acute erosive gastritis is an acute gastritis characterized by multiple erosions of the gastric mucosa, often accompanied by bleeding. Oral medications (such as salicylate preparations, bosozone, anti-inflammatory pain, reserpine, glucocorticoids, etc.), alcohol abuse and stressful states of critical illness are its common causes. The typical clinical manifestation of the disease is upper gastrointestinal bleeding with vomiting of blood and black feces; however, the bleeding is usually small and often intermittent, and can stop on its own. The principle of treatment for acute erosive gastritis is to actively treat the primary disease, remove the causative factors, and do the appropriate acid control and hemostatic treatment. If the upper gastrointestinal bleeding should be promptly given blood transfusion, fluid transfusion, and active blood volume replenishment. 3, acute corrosive gastritis: acute corrosive gastritis is caused by swallowing strong alkali, strong acid or other corrosive agents and damage to the gastric mucosa. The gastric lesions in the lighter manifestations of mucosal congestion, edema, erosion, the heavier can have acute ulcers, gastric wall necrosis or even perforation. The disease is characterized by burning and choking sensation in the mouth and throat, edema of the tongue, salivation and difficulty in swallowing after swallowing corrosive agents, and severe pain in the posterior sternum and upper abdomen, as well as continuous eructation, vomiting, coughing, fever up to 38℃-39℃, difficulty in breathing, and in severe cases, blood in the vomitus, deficiency, shock and even mediastinitis and peritonitis due to esophageal and gastric perforation. This disease is a serious medical emergency, must be rescued early and actively, monitoring vital signs, applying antidotes, nutritional support and antibiotics to prevent and control infection. 4, acute suppurative gastritis: acute suppurative gastritis is a septic lesion caused by bacterial infection of the stomach wall. The most common causative agent is Streptococcus, followed by Staphylococcus and S. pneumoniae and E. coli. Respiratory or other infections, gastric ulcers, removal of gastric polyps, and gastric surgery are its triggers. The disease has a rapid onset and is characterized by chills, high fever, severe pain in the upper abdomen, nausea, vomiting, and occasionally purulent vomitus. Once the disease is diagnosed, surgery should be given immediately and high-dose antibiotics should be used to control the infection, correct shock, and maintain water and electrolyte balance. Etiology: 1, physical factors Too cold, too hot food and drinks, strong tea, coffee, alcohol, harsh condiments, too rough food can stimulate the gastric mucosa and destroy the mucosal barrier. 2, chemical factors Aspirin and other drugs interfere with the synthesis of thioglycoprotein in the epithelial cells of the gastric mucosa, so that the gastric mucosa is reduced, the protective effect of lipoprotein film is weakened, resulting in the pathological process of gastric mucosa congestion, edema, erosion and bleeding, prostaglandin synthesis is inhibited, and the repair of gastric mucosa is also affected. 3, biological factors bacteria and their toxins. Common pathogenic bacteria are Salmonella, Salmonella, pathogenic Escherichia coli, etc. Common toxins are Staphylococcus aureus or toxin bacillus toxin, especially the former is more common. Gastritis can occur after a few hours of eating food contaminated with bacteria or toxins or combined with enteritis which is acute gastroenteritis. Staphylococci and their toxins can also be combined with enteritis after ingestion, and the onset is more rapid. In recent years, viral infections have been causing more and more cases of this disease. 4, mental, neurological factors mental, neurological dysfunction, the critical state of various acute illnesses, as well as the body’s allergic (allergic) reactions can cause acute inflammatory damage to the gastric mucosa. 5, foreign body in the stomach or gastric stone, gastric area radiation therapy can be used as exogenous stimulation, leading to the disease.