Until quite recently, the accepted medical view was that ulcers were triggered mostly by stress (which disturbed the production of stomach acid) or by medications such as NSAIDs (non steroidal anti inflammatory drugs) or aspirin, and were probably aggravated further by spicy or smoked foods and excess alcohol.

Ulcers can occur in the oesophagus, stomach or duodenum (upper part of the small intestine). Statistics from the US show that one in every 10 people develops an ulcer; half a million new cases are diagnosed every year; and more than a million people end up in hospital, often as a result of complications and/or late diagnosis. Left untreated, the lining of the stomach or intestines will be destroyed, risking internal bleeding, vomiting of blood or blood in the stools. Even more serious is the possibility of perforation, where a hole in the membrane allows previously contained contents (partially digested food, for example) to spill into the abdominal cavity, causing contamination, infection, inflammation and life threatening trauma.

The remedy most favoured, the milk based diet, is now recognised as being a poor protector against ulcer attack. Although it may soothe for a few seconds, once milk hits the stomach, it stimulates the secretion of even more acid, akin to pouring pints of acid over a raw wound, causing intense pain and further damage to the ulcerated area. Barbiturates, antacids, semi comatose bed rest, stress management techniques, psychodrama and, latterly, more sophisticated (and expensive) attempts have all come (and gone) as the treatments of choice.

Dedicated research by Australian doctors Barry Marshall and Robin Warren has now turned established practice on its head. They found a common bacterium called Helicobacter pylori nestling in the gut of a significant number of ulcer sufferers and dared to suggest that this bug could be the actual cause of ulcers. Similar work was carried out by a team at the Western Infirmary in Glasgow led by Dr Kenneth McColl.

Helicobacter pylori, a new name for an old bug, is still sometimes known as Campylobacter pylori. It sets up home in the narrow space between stomach lining and the mucous covering that tries to protect the stomach wall from damage. Worryingly, it is now considered a more prolific bug than salmonella and is now classified a class A carcinogenic, equal to asbestos and cigarettes.

Marshall and Warren tried to interest the medical establishment in their discovery but met with a wall of apathy and indifference. Doctors have believed for years that bacteria can't survive in stomach acid. In fact, this belief was so firmly held many medics didn't follow even basic hygiene rules, unwittingly passing the bacteria from patient to patient during surgery. No one imagined for a moment that ulcers could be contagious.

Marshall and Warren caused further furore by suggesting that short term treatment with the right kind of antibiotics (usually a cocktail of two different ones with bismuth and sometimes antacids referred to as the "triple therapy") cured 95 percent of cases. So convinced was Dr Marshall that (at Freemantle Hospital in Western Australia) he used himself as the first guinea pig, swallowed a heavy suspension of the offending bacteria, gave himself an ulcer and then cured it with antibiotic therapy.