How did Dr. Barry Marshall confirm his hypothesis regarding Helicobacter pylori?

He famously ingested a broth containing the bacteria himself.

Dr. Barry Marshall demonstrated extreme conviction in his hypothesis that Helicobacter pylori caused peptic ulcers, which was contrary to the long-held belief that stress or diet were the primary causes. To definitively prove his claim, Marshall intentionally consumed a broth containing the specific bacterium. Following this ingestion, he developed gastritis, which served as a direct, personal confirmation that the microbe was indeed the causative agent for the condition. This self-experimentation was a legendary act that established one of the earliest, most specific links between a single gut microbe and a distinct human ailment, thereby validating the approach of linking specific pathogens to testable diseases.