Last month brought welcome news for nicotine junkies everywhere. According to press reports from an American conference, “new research” suggested that “smokers who’ve tried but failed to kick their habit may want to pop a daily aspirin, ibuprofen or naproxen (Aleve) to help cut their risk of mouth cancer”.

The reports, however, neglected to mention the other side of the coin: that these painkillers cause more medical emergencies than any other pharmaceutical product. “Research”, in fact, suggests that stomach bleeding triggered by these so-called “non-steroidal anti-inflammatories”, or NSAIDs, leads to about 3,500 hospitalisations and 400 deaths among Britons over 60 each year.

Family doctors are exasperated by patients demanding new drugs or treatments based on what they read. “Patients come in all the time under the influence of these stories,” says Dr Mike Fitzpatrick, an east London GP. “Like cholesterol-lowering drugs. One minute new research says they are better than we thought. Then more new research links them with serious side effects.”

Maybe somebody should start a league table to rank the credibility of the new research’s sources. The mouth cancer research, for instance, is the baby of Dr Jon Sudbo, a consultant oncologist at Norway’s Rikshospitalet and, until recently, an adjunct professor at the reputable Oslo University.

Reporting last October in The Lancet, once the flagship of British medical publishing, Sudbo and a team of 13 other doctors laid out an impressive nine pages of text, tables and statistics pointing to the painkillers’ benefits.

That seems to nail it. But on the other hand, the stomach research’s source is impeccable. The risks of painkillers and bleeding are most notably the work of Professor Michael Langman, who is not only the former dean of medicine at Birmingham University, but also sat for many years on the government’s late committee on safety of medicines. He is an expert’s expert.

No assistance yet, then, with Fitzpatrick’s dilemma. As a wise aunt of mine regularly advised me in my younger and more vulnerable years: “Believe nothing you hear and hardly anything you see.”

If you have the time, however, further inquiry helps. For instance, Sudbo has recently joined a growing list of doctors and scientists who have been condemned by their colleagues as cheats. Amazingly, two months before the press reports announcing his dramatic “new research” for smokers, The Lancet had published a worrying 52-word statement buried on a left-hand page.

“We have received confirmation,” Dr Richard Horton, the journal’s beleaguered editor, admitted, “that the paper published by Jon Sudbo and colleagues in The Lancet contains fabricated data . . . and we now retract this article in full.”

This inclines me to think that Langman’s research is the weightier of the two. If I smoked, I wouldn’t also “pop aspirin”. True or false, Sudbo’s suggestion should therefore perhaps be considered a sort of urban myth — like advice to pregnant women to smoke fags for a smaller baby and that inhaling blue asbestos clears the lungs.

What about this Langman chap? This is a tricky one. Langman is no faker. Yet his enthusiasms have sometimes run amok. A Sunday Times investigation revealed last summer that, while sitting on the government’s drug safety watchdog, in April 1999 he flew to the United States for the Merck drug company and lobbied regulators in support of Vioxx, Merck’s painkiller which was later withdrawn after an epidemic of heart deaths. Ooops.

“There is a crisis of credibility in medicine and science,” says Dr Joseph Sonnabend who, as a former virologist for the Medical Research Council and a retired Aids physician, has watched the basis for public confidence decline. “Less and less information seems purely disinterested. You have to check everything out.”

If you cannot always trust the doctors, however, what about the journals in which they write? About half the top 20,000 medical titles trumpet their status as being “peer reviewed”, which means that research is supposed to be vetted before publication: not merely with a “spellchecker” but by relevant specialists.