Health obsessives will be breaking out in a sweat when they read the latest research: browsing medical websites can be bad for you.

Researchers have spent 18 months studying internet resources that offer advice on the symptoms and treatment of illnesses from colds to cancer. Dr Neil Coulson, who led the research team at the University of Derby, said: "We found that people using these sites can take on board medical advice which is incorrect, an obvious concern. Indeed, the health profession has coined the term cyberchondria for people using the internet for self-diagnosis and presenting this misinformation to their GP."

The study examined sites dedicated to helping sufferers and carers of people with skin disorders, HIV and Aids, diabetes, cancer and Huntingdon's disease. It found that most sites connected to societies, charities or professional bodies offered sound advice, but that those set up by individuals could include glaring inaccuracies.

The team has urged health professionals to offer information and guidance to any website they discover that contains mistakes or untruths, in the hope of stopping misunderstandings.

The report also, however, praised the internet for offering support. Dr Coulson said: "A carer looking after a housebound relative, without compromising the care of their relative, can log on to the internet at whatever time they like, and a support community is available made up of people in the same position, experiencing the same emotions."