What is the most common cause of stomach ulcers?

Helicobacter pylori is the most common cause of stomach ulcers. This bacterium infects the lining of the stomach and weakens the protective mucus layer, allowing stomach acid to damage the sensitive stomach lining. It is estimated that around 80% of stomach ulcers are caused by H. pylori infection. Other factors such as stress, certain medications like NSAIDs, and rare conditions like Zollinger-Ellison syndrome can also contribute to the development of stomach ulcers, but H. pylori infection is the primary cause.