Barry Marshall
Barry James Marshall (born 30 September 1951) is an Australian physician, Nobel Laureate in Physiology or Medicine, Professor of Clinical Microbiology and Co-Director of the Marshall Centre at the University of Western Australia. Marshall and Robin Warren showed that the bacterium Helicobacter pylori (H. pylori) plays a major role in causing many peptic ulcers, challenging decades of medical doctrine holding that ulcers were caused primarily by stress, spicy foods, and too much acid.