Quality cannot always be assured on the web
The amount of health information available on the internet has exploded in recent years.
One study found that the standard of information contained in public oriented sites had improved.
However, another concluded that apparently credible websites may not be accurate.
And a third found that most popular websites were not necessarily of the highest quality.
Dr Khalid Khan and his team from Birmingham's Women's Hospital examined the content of 121 websites that provide information on five common health topics:
A team from the University of Texas focused on the quality of websites giving information about breast cancer.
They found that the more popular websites were not necessarily of higher quality, and were just as likely to contain inaccurate information as less popular sites.
Good news
However, a third study carried out by researchers at the Istituto di Ricerche Farmacologiche in Milan, found that the quality of health information on the internet has improved over the past few years.
The Italian team focused on websites giving information about managing fever in children at home.
They initially assessed quality in 1997 and again four years later.
They found that 45% of the new pages adhered to most of the accepted guidelines compared to just 8% of the original papers.
The UK Government has set up a National Electronic Library for Health in response to concerns from the medical profession about the quality of information available on the web.
Benefits
Dr Paul Cundy, a member of the British Medical Association's IT committee, said: "This study confirms our suspicions, but it is a good sign that some sites are getting better."
Dr Cundy said the web did have benefits if used sensibly.
"I advise some people to go on the web. It gives me the opportunity to save time and to do other things.
"For instance, instead of giving men who are worried about whether they should go for prostate screening a 10-15 minute dissertation, I now advise them to look it up on the web, and to come back to me if they still think they need a test."