Google needs to do a better job controlling its advertisements and suggested links to avoid providing users with web pages that contain dubious and sometimes dangerous medical claims, warn doctors in an article published on bmj.com, the British Medical Journal website.

Dr. Marco Masoni and colleagues at the University of Florence in Italy set their sights on Google AdWords, a service that matches key search terms to related advertising.

The authors note that AdWords is "Google's flagship advertising product" and was its "main source of revenue in 2007."

Using AdWords, businesses can create advertisements and choose their own keywords, and decide which Google searches should match their advertisements. Google decides on placement on its pages of search results: which advertisements to show and in what order.

But Google's automated matching system sometimes places inappropriate advertisements, say the authors. For example, they write that they recently used Google Italia to search on the keyword "aloe" and found sponsored links to websites recommending aloe arborescens for the prevention and treatment of cancer - a use that has no basis in science.

While Google has reportedly improved its filters in recent years, the authors argue that the filters need to be improved further.

The authors conclude that if Google wishes to enter the healthcare arena, as it has often said it does, "...We think that a necessary first step for Google is to improve its filters and algorithms so as to prevent possible harm to its users."

The authors add that since websites advertising bogus or suspect products are not well policed, it is up to members of the medical community to suggest improvements.

In a second article on bmj.com, Joanne Shaw from NHS Direct, a health advice and information service provided by the National Health Service (NHS) in England, says the Internet is transforming health care.

"The internet has brought the canon of medical knowledge into the hands and homes of ordinary people, and this should be welcomed and encouraged as good for patients and doctors alike," she writes.

While much of what patients find on the Web may worry them needlessly, there is also plenty of legitimate information that informs patients and may even encourage them to take actions that could improve their survival, she writes.

Those patients who look to the Internet as a legitimate tool to help them with their health may already be in the majority and this is something for us to celebrate, she concludes.