For decades the medical community believed gastric ulcers were directly related to stress with the only options for relief being antacids and surgery. In the early 1980’s, Australian physicians Barry Marshall and Robin Warren discovered through biopsies of gastric ulcers, that nearly all were overrun by helicobacter pylori bacteria. Helicobacter pylori only seems to infect humans, as studies performed upon pigs and rats were unsuccessful as these animals were unable to contract the bacterium. Marshall decided to infect himself and within 5 days of doing so, he started running to the bathroom each morning to throw up. Tests demonstrated that Marshall had gastritis, a precursor to an ulcer. Marshall took antibiotics and was cured, proving once and for all that ulcers are caused by bacteria not stress. In 2005, Marshall and Warren won the Nobel Prize in Medicine for their findings