Patients should not place "false hope" in promises made by untested internet miracle cures, medical experts warned today.
Independent medical charity Sense About Science said many vulnerable patients are being duped by "surreptitious promotion and misleading stories" online and spending thousands of pounds on drugs that might be nothing more than snake oil.
The charity said it is worried about "the emotional and financial costs of over-hyped treatment claims that sell false hope".
Tracey Brown, managing director of Sense About Science, said: "We've been contacted by so many people exhausted from the pressure they feel to try advertised treatments, dietary regimes and exercises.
"One person told us how the last years of his wife's life were spent endlessly pursuing new treatments, from goats blood serums to unlicensed stem cell treatments abroad, all to no avail."
To assist, the charity has published a guide called I've Got Nothing to Lose by Trying It that explains how to tell the beneficial drugs from the bogus.
The guide has received the backing of the Royal College of GPs whose vice-chairman, Dr Clare Gerada, said: "This guide provides a wealth of sensible information to patients and the public.
"It goes a long way to taking the mystery out of medicine and I would recommend it to patients as a common-sense read."
Patients suffering from Parkinson's disease, multiple sclerosis and motor neurone disease are particularly targeted.
Dr Kieran Breen, director of research with the Parkinson's Disease Society, explained how patients are prepared to try anything to ease their suffering.
He said: "It can be tempting to believe personal stories of miracle cures, but only by using tried and tested methods can we move forward and provide people with Parkinson's with the best available advice and treatments."
The campaign has also secured the political support of Liberal Democrat MP Phil Willis, who is chairman of the Innovation, Universities, Science and Skills Select Committee.
The politician said: "The cruellest deception for a patient with a chronic illness is the promise of a cure based on empty hope, not evidence.
"The publication of I've Got Nothing to Lose by Trying It is an inspired attempt to empower patients to evaluate so-called 'miracle cures' with evidence-based advice."
:: The guide can be downloaded from http://www.senseaboutscience.org.uk or ordered free from 020 7478 4380.Reuse content