Edema and congestion of the esophageal mucosa is caused by esophagitis. Esophagitis (esophagitis) is an inflammation of the esophageal mucosa caused by edema and congestion of the esophageal mucosa due to abnormal stimulation of the superficial or deep tissue. Causes: 1. Swallowing hot food, sharp foreign objects or insufficiently chewed bones, and accidental ingestion of corrosives directly damage the esophageal mucosa causing inflammation. Veterinary personnel to dogs and cats with gastric catheter instillation, rough use of gastric catheter, often can damage the esophageal mucosa. 2, antibiotics used for too long, resulting in infection caused by the proliferation of fungal esophageal mucosa. 3, secondary to inflammation of the pharynx or stomach; esophageal spasm, dilation, paralysis, tumors can cause chronic esophagitis. 4, stimulating food, drinking, strong coffee, strong tea, etc., can cause damage to the esophageal mucosa and trigger inflammation. 5, physical factors: such as radiation, X-rays, CT, etc. The symptoms of esophagitis are mainly painful swallowing, difficulty, heartburn and pain behind the sternum, and when esophagitis is severe it can cause esophageal spasm and esophageal stricture. When the lower esophagus is inflamed and the mucosa degenerates and then the columnar epithelium of the stomach grows, it is called Barlow’s esophagus, which is the precursor of esophageal cancer and must be followed for a long time.