The route by which humans get infected with H.p. is unknown. Viable bacteria have been shown to be excreted in human feces from infected individuals. We have recently shown that flies are able to carry and disseminate viable H. p. with their excreta, when they have fed on H.p. We propose a hypothesis that H. p. is acquired from human feces by flies, which then, while crawling on human food, contaminate it with their intestinal excreta. The food, swallowed by a susceptible individual then leads to a new infection. Flies should be considered prime suspects for the transmission of H. p., particularly in developing countries, where sanitary and domestic facilities are poor.