Bombarded with unsubstantiated claims for 'pioneering cancer treatments', new diets and unfounded stem cell cures, patients say they have been left 'chasing false hope', exposed to crippling financial and emotional costs and risked serious harm to their health.

They are publishing a guide[1] in collaboration with medical charities[2] and Sense About Science, to help people weigh up claims about 'miracle cures' on the web and in advertising.

People facing long-term or chronic conditions - cancer, degenerative conditions such as multiple sclerosis or motor-neurone disease, autism, epilepsy, Alzheimer's - can be desperately searching for anything that might help, and especially vulnerable to exploitation.

Patients and carers have experienced: aggravation of their condition, pressure to stop taking medication, being exposed to risk of infections such as HIV via treatment with unscreened stem cells, parting with life savings, risking loss of homes or jobs, pressure from well-meaning friends and family to try things despite a lack of evidence to support them, and disappointment when they realise they have been sold false hope.

Some of these treatments cost tens of thousands of pounds. This runs into hundreds of thousands if they involve costly trips to private clinics abroad - this has prompted high-profile emotional public appeals from family and friends to raise money for treatment costs.

The internet crosses national boundaries and gives near-endless space for claims, and the rise in people seeking medical information online has increased the bombardment people experience. People regularly use the internet to look further into a specific scientific or health topic[3] - 80% of UK adults now have internet access[3].

The guide, I've got nothing to lose by trying it, shares things people can do - from getting involved in clinical trials to finding good evidence based information - and explains the questions people can ask about evidence to help tell the beneficial from the bogus and hold these claims at bay.

Patient stories are available in full from Sense About Science

Comments - from patients:

Christine, who has a thyroid condition: "After a saliva test an 'alternative thyroid doctor' gave me 'adrenal glandular' tablets and told me to reduce my prescribed thyroid medication. I was in a lot of pain, bed-bound for weeks and it cost me a whole year out of my life - not to mention the huge costs of paid carers and useless and misleading saliva tests. My advice is not to make my terrible mistake of trusting anyone outside the medical profession."

Fiona, a cancer patient: "I left my appointment feeling utterly powerless. I hope that from now on vulnerable people who are suffering emotionally will not need to have such a horrible experience when they go to see someone who they think would help them."

Anne-Louise Crocker, who has two children with autism: "Autism is one of those conditions, as yet not much understood by medical science, which just naturally cause a vacuum into which rushes every type of quackery. Since my older daughter was diagnosed 10 years ago, I've been urged to try all manner of "miracle cures" from chelation to oxygen chambers, from exclusion diets to injections of pig hormones. Many parents will try them on the "what harm can it do?" principle - though some can be harmful."

From patient groups & medical charities:

Dr Emma Gray, Research Communications Manager, MS Society: "Making decisions about what treatment to take can be difficult for people with MS - there's so much information out there, it can be hard to know what to trust and believe. We understand there can be a temptation to try unlicensed treatments, but this comes with a safety risk - I would encourage anyone considering a new treatment to examine the evidence and then talk this through with a healthcare professional."

Julia Wilson, Director of Research, Breakthrough Breast Cancer: "There's a lot of health information out there, but not all of it useful, helpful or safe, so this unique guide will navigate patients and their families through the wealth of complimentary therapies, and enable them to sort the sensible from the spurious. We know that many women with breast cancer try complementary therapies to help with the side effects of their treatment; it's important that they are able to make informed choices about treatments they know to be safe and effective, and make decisions that are right for them, which is where this guide will prove invaluable."

Jess Smith, Research Communications Officer, Alzheimer's Society: "With so many press articles and web pages about dementia, it can be difficult for people to understand what has good evidence behind it and what doesn't. We want to make sure that people affected by dementia can have access to the best information, and this booklet is a great way to help them to assess the benefits of what they read about."

Tracey Brown, Managing Director, Sense About Science: "If a claim about a treatment sounds too good to be true, it probably is. Families and friends can help loved ones to ask questions and avoid exploitation. We can all make steps towards a culture change on unproven treatments."

Belinda Cupid, Head of Research, MND Association, UK: "There is a wealth of information, reports and testimonies on unproven treatments available on the internet. These 'so-called' treatments range from coconut oil to stem cells, from dietary supplements to unusual diets. We appreciate how frustrating it is for people living with MND and their need for more effective treatments to be made available. However, research must be thorough and properly evaluated, which does take time. It is vital for people living with or affected by MND to have all the information, to enable them to make their own decisions. The Sense About Science guide will help distinguish fact from fiction and prove invaluable to so many people."

Delphine van der Pauw, Research & Information Executive, Epilepsy Research UK: "There is no cure for epilepsy, and current treatments are far from perfect. People with epilepsy need to be informed of clinical advances, but they must also be given a realistic idea about if and when new therapies might become available. Unfortunately we have seen the media and online marketing claims mislead people using false statements about life-changing treatments (such as stem cell therapy or homeopathy), and this has led to bitter disappointment. At Epilepsy Research UK we hope that by supporting this guide we will help to increase awareness of this problem, and encourage people to challenge the claims that they encounter."

Liz Woolf, Head of Cancer Web Content, Cancer Research UK: "We are very happy to support this initiative. Through our patient information services, Cancer Research UK is well aware how distressing this kind of misinformation about 'cures' for serious illnesses can be for people. It gives them false hope and can lower their confidence in the treatment they are receiving from their own doctors. We hope the guide will help people to decide for themselves whether information they find about alternative therapies has evidence to support it."

From advocates of evidence-based medicine:

Derren Brown, illusionist: "Curiosity is at the heart of what makes us great. To not just mindlessly believe what we're told, but to know how to question and test a claim, has lifted us from the Dark Ages. And when the vacuous and untested assertions of health products and celebrity endorsements, of psychics and faith healers, of politicians, religious leaders and journalists go routinely unquestioned, we are put at risk. But we need the understanding and the tools to question these claims in order to know what we should believe."

Professor Robin Lovell-Badge, Head of the Division of Stem Cell Biology and Developmental Genetics at the MRC National Institute for Medical Research: "Stem cell therapies are still in the early research stages for most conditions. The UK is at the forefront of pushing the boundaries, and there is reason to be optimistic, but realistically it takes many years for new treatments to be proven safe and worthwhile. Unregulated clinics take people's money and hope, putting them at risk of complications, even HIV or hepatitis, for no benefit."

Professor Martin Wiseman, World Cancer Research Fund: "There's so much information about how we can prevent or cure diseases - whether it's on the TV, in a newspaper or just gossip. Some of it is accurate but lots is either half the story, distorted or just plain wrong. How can we know what's accurate and what's not? Keep asking questions and it's usually possible to sift the truth from the fiction."

Ammar Al-Chalabi, Professor of Neurology and Complex Disease, King's College London: "Many people with Motor Neurone Disease seek out unproven treatments because of the very difficult situation they and their families are in. I see people who are desperate, spending tens of thousands of pounds on treatments that are definitely pointless, like stem cell therapy consisting of giving an unknown substance intravenously at an unlicensed clinic. I see others who shun conventional medicine because they believe in alternative therapies. As medical staff we have an ethical obligation to provide clear advice in these situations."

Sir Iain Chalmers, Coordinator, James Lind Initiative: "Most people aren't aware that, on average, new treatments turn out to be almost as likely to be worse as they are to be better than existing treatments. The new edition of I've got nothing to lose by trying it is a reminder to be sceptical of claims about the effects of treatments which are not supported by systematic reviews of relevant research. And that means taking account of all relevant research, as demanded by the AllTrials campaign, calling for all clinical trials should registered and reported."

Dr Margaret McCartney, GP: "I am passionate about people being able to make good decisions about their health. But breakthroughs are rare, and false hope, hype and overselling of unproven or uncertain treatments are everywhere. As a GP I see the harms this does - it's incredibly unfair. We need to be honest about our knowledge, to fairly explain when we aren't sure, and to be upfront about conflicts of interest. Otherwise everyone loses."