Barry James Marshall, AC

Order of Australia

The Order of Australia is an order of chivalry established on 14 February 1975 by Elizabeth II, Queen of Australia, "for the purpose of according recognition to Australian citizens and other persons for achievement or for meritorious service"...

, FRS, FAA (born 30 September 1951) is an Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

n physician

Physician

A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...

, Nobel Prize

Nobel Prize

The Nobel Prizes are annual international awards bestowed by Scandinavian committees in recognition of cultural and scientific advances. The will of the Swedish chemist Alfred Nobel, the inventor of dynamite, established the prizes in 1895...

 laureate in Physiology

Physiology

Physiology is the science of the function of living systems. This includes how organisms, organ systems, organs, cells, and bio-molecules carry out the chemical or physical functions that exist in a living system. The highest honor awarded in physiology is the Nobel Prize in Physiology or...

 or Medicine

Medicine

Medicine is the science and art of healing. It encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness....

, and Professor of Clinical Microbiology

Microbiology

Microbiology is the study of microorganisms, which are defined as any microscopic organism that comprises either a single cell , cell clusters or no cell at all . This includes eukaryotes, such as fungi and protists, and prokaryotes...

 at the University of Western Australia

University of Western Australia

The University of Western Australia was established by an Act of the Western Australian Parliament in February 1911, and began teaching students for the first time in 1913. It is the oldest university in the state of Western Australia and the only university in the state to be a member of the...

. Marshall is well-known for proving that the bacterium Helicobacter pylori

Helicobacter pylori

Helicobacter pylori , previously named Campylobacter pyloridis, is a Gram-negative, microaerophilic bacterium found in the stomach. It was identified in 1982 by Barry Marshall and Robin Warren, who found that it was present in patients with chronic gastritis and gastric ulcers, conditions that were...

(H. pylori) is the cause of most peptic ulcer

Peptic ulcer

A peptic ulcer, also known as PUD or peptic ulcer disease, is the most common ulcer of an area of the gastrointestinal tract that is usually acidic and thus extremely painful. It is defined as mucosal erosions equal to or greater than 0.5 cm...

s, reversing decades of medical doctrine holding that ulcers were caused by stress, spicy foods, and too much acid.

Marshall was born in Kalgoorlie

Kalgoorlie, Western Australia

Kalgoorlie, known as Kalgoorlie-Boulder, is a town in the Goldfields-Esperance region of Western Australia, and is located east-northeast of state capital Perth at the end of the Great Eastern Highway...

, Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

 and lived in Kalgoorlie and Carnarvon

Carnarvon, Western Australia

Carnarvon is a coastal town situated approximately 900 kilometres north of Perth, Western Australia. It lies at the mouth of the Gascoyne River on the Indian Ocean. The popular Shark Bay world heritage area lies to the south of the town and the Ningaloo Reef lies to the north...

 until moving to Perth

Perth, Western Australia

Perth is the capital and largest city of the Australian state of Western Australia and the fourth most populous city in Australia. The Perth metropolitan area has an estimated population of almost 1,700,000....

 at the age of seven.