Barry Marshall marries Adrienne, a psychology student.

Barry Marshall moves back to Royal Perth Hospital where, funded by the Australian Medical Research Council, he conducts a prospective double blind trial to see if antibiotics can cure duodenal ulcers.

After failed attempts to infect piglets, Barry Marshall swallows a solution of the bacterium Helicobacter pylori, develops the infection, including inflammation of the stomach, and cures himself of both the infection and the stomach inflammation by antibiotic therapy demonstrating that ulcers are curable in this way instead of taking antacids or having to undergo surgery. This experiment is published in 1985 in the "Medical Journal of Australia".

Barry Marshall gets in touch with Dr Martin Skirrow, who arranges for the first presentation at the European Campylobacter Meeting. Gist Brocades Company gives him the possibility to extend the trip, and to visit Skirrow in the UK and Guido Tytgat's group in Amsterdam. In the United Kingdom he finds that the spiral bug is not merely an Australian phenomenon but it is present in ulcer patients in the UK as well.

Barry Marshall is born in Kalgoorlie, Western Australia, the eldest of four children to Robert Marshall, a pipefitter. His mother is eighteen years old when he is born, and she quits her nursing training. After a couple of years after Marshall's birth, the family moves to Carnarvon, then to Kalgoorlie until the family relocates in Perth, when Marshall is eight. Since an early age Marshall shows an exuberant and inquisitive nature.

Barry Marshall enters University of Western Australia, where he receives a Bachelor in Medicine and Surgery.

Drs. Norm Marinovich and Ian Hislop offer Barry Marshall a senior registrar position at Fremantle Hospital to help him continue his researches. Here he confirms the observations made at the Royal Perth Hospital and the first effective treatments are devised.

Barry Marshall takes a year of leave from the university. During this year he travels, lectures but his primary work is getting the breath test through the FDA regulatory process.

Barry Marshall performs internship and residencies in internal medicine at the Queen Elizabeth II Medical Centre (Sir Charles Gairdner Hospital). He begins his training as a specialist physician in 1978.

Barry Marshall is appointed McFarlane Burnet Fellowship which funds his laboratory at the University of Western Australia. In 1997 he is appointed Clinical Professor of Medicine. In 1999 he is Clinical Professor of Microbiology and in 2003 he becomes NHMRC Senior Principal Research Fellow.

Barry Marshall attends Newman College. During these years he enjoys making electromagnets as well as reading medical and nursing books. One of his favourite book as a child is an old Newne's Children's Encyclopaedia in which he finds interesting experiment to conduct. He builds a slingshot, a crystal set, a Morse-code set, various guns, a hydrogen generator for balloons, electric devices and he creates several explosive mixtures to make firecrackers and bombs.

Marshall moves to the Royal Peth Hospital to deepen cardiology and open heart surgery. In 1981, Marshall starts working in the gastroenterology division with Robin Warren on patients with curved bacteria present on their stomach biopsies. They culture the bacterium, which they name Helicobacter pylori. Despite their evidence that the organism is the cause of stomach ulceration, the medical community doesn’t believe that a bacterium can survive the harsh acidic conditions of the stomach.

Barry Marshall receives half of the Nobel Prize in Physiology or Medicine along with J. Robin Warren "for their discovery of the bacterium Helicobacter pylori and its role in gastritis and peptic ulcer disease".

The National Institute of Health holds a consensus meeting in Washington DC which ends with the statement that the key to treat both duodenal and gastric ulcer is to detect and eradicate Helicobacter pylori.

Barry Marshall accepts a part-time appointment at the Pennsylvania State University spending there part of the spring semester each year.

Barry Marshall joins the University of Virginia. During this period he extends his research, particularly in the area of treatment and diagnostics. He develops an enzyme-based rapid test for the presence of the bacterium that tests patient's breath.