Common causes of upper gastrointestinal bleeding include gastric ulcers, duodenal ulcers, gastrointestinal tumors, and even vascular malformations. Upper gastrointestinal bleeding is a medical emergency in the field of internal medicine and is generally treated in gastroenterology or emergency departments. Most patients present with vomiting blood or having bloody stools. Of course, patients with significant bleeding may experience symptoms of low blood volume such as dizziness, fatigue, chest tightness, and palpitations. Therefore, patients with the aforementioned symptoms are advised to seek timely treatment in the gastroenterology or emergency department. It is recommended to complete routine blood tests, electrocardiograms, and gastroscopic examinations. If necessary, further examinations such as colonoscopy or abdominal CT scans should be done to determine the cause. The treatment is primarily supportive at this stage, including fasting, rest, and monitoring vital signs. For medication, active fluid replenishment and anemia correction to improve low blood volume symptoms are recommended. Different causes require different treatment plans. If an ulcer is suspected, acid-suppressing and stomach-protecting medicines may be added. If tumor bleeding is considered, surgical intervention is generally required.