Australian physicist who won the 2005 Nobel Prize in Physiology or Medicine for discovering that peptic ulcers were a result of a bacterial infection (Helicobacter pylori) and not due to stress, spicy foods or development of excess acid.
His discovery was much derided in scientific circles as it was contrary to old medical doctrines. Marshall, however, took a drastic step and confirmed his theory by inducing ulcers on himself after consuming a petri-dish of the bacteria.
