Edema and congestion of the esophageal mucosa is caused by esophagitis. Esophagitis (esophagitis) is an inflammation of the superficial or deep tissue of the esophageal mucosa due to abnormal stimulation and edema and congestion of the esophageal mucosa. Etiology: 1. Hypofunction of the lower esophageal sphincter: In normal people, there is a high-pressure zone in the lower esophageal tract muscle that prevents reflux of gastric contents into the esophagus. Many reasons can make the lower esophageal sphincter function weakened, including esophageal hiatal hernia, which easily causes regurgitation of gastric and intestinal contents into the esophagus and is the main cause of inflammatory lesions in the esophageal mucosa. 2, increased abdominal pressure: such as a large amount of ascites, pregnancy, resulting in increased abdominal pressure, prone to the formation of reflux. 3, esophageal peristaltic disorders: under normal circumstances, when the stomach contents reflux into the esophagus, the effect of tension causes secondary peristaltic waves in the esophagus, sending the reflux back into the stomach. Esophagitis can slow down the peristalsis of the esophagus, making the reflux stay longer in the esophagus, aggravating the original esophagitis, and esophagitis weakens the function of the lower esophageal sphincter, aggravating reflux, forming a vicious circle. 4, swallowing hot food, sharp foreign objects or inadequately chewed bones, accidental ingestion of corrosive agents and other direct damage to the esophageal mucosa caused by inflammation. Veterinary personnel to dogs and cats with gastric catheter instillation, rough use of gastric catheter, often can damage the esophageal mucosa.