What is the most common cause of upper gastrointestinal bleeding?

Peptic ulcer disease is the most common cause of upper gastrointestinal bleeding. This condition arises when there are ulcerations in the gastric or duodenal lining due to factors such as infection with Helicobacter pylori, prolonged use of non-steroidal anti-inflammatory drugs (NSAIDs), or excessive alcohol consumption. These ulcers can erode into blood vessels, leading to significant bleeding, which may present as hematemesis (vomiting blood) or melena (black, tarry stools).

In contrast, while esophageal varices can indeed cause upper GI bleeding, they are typically more associated with portal hypertension and liver disease. Gastric cancer is a less common cause of Upper GI bleeding compared to peptic ulcers, as it occurs with a lower incidence and often presents with other systemic symptoms. Gastroesophageal reflux disease (GERD) typically does not cause upper GI bleeding; it is primarily characterized by symptoms related to gastric acid reflux into the esophagus.

Thus, recognizing that peptic ulcer disease is prevalent, especially in populations at risk, establishes it as the most common and clinically relevant cause of upper gastrointestinal bleeding.