What is the most common cause of massive upper gastrointestinal bleeding?

A large amount of upper gastrointestinal bleeding may be caused by gastric ulcer, duodenal ulcer, esophageal varices, liver cirrhosis, portal hypertension, esophageal hiatus hernia, esophagitis, etc. When the patient has more bleeding, it is necessary to follow the doctor's advice to treat with hemostatic agents, and also need to do digestive tract examination. Usually, it is necessary to give the patient timely fluid replacement and electrolyte supplement.