Upper gastrointestinal bleeding generally refers to bleeding caused by esophageal, gastric, and duodenal lesions, which clinically manifests most commonly as vomiting blood and blood in stools. Of course, some patients may also experience symptoms such as dizziness, fatigue, and chest tightness. Common causes to be aware of include inflammation, ulcers, tumors, and vascular malformations, especially gastric and duodenal ulcers which are relatively common in clinical settings. The fastest diagnosis mainly relies on gastroscopy, thus it is recommended that patients who suspect upper gastrointestinal bleeding should undergo a gastroscopy as soon as their condition stabilizes to determine the specific cause of the bleeding, such as digestive tract ulcers or even tumors. For treatment, conservative medical management is initially advised, focusing on aggressive fluid replenishment, acid suppression for gastric protection, and blood volume supplementation. Once the gastroscopy provides a clear diagnosis, the treatment plan should be promptly adjusted.