Doctors are calling on internet search engine Google to change its advertising policies to prevent links to unproven remedies appearing when patients search for medical information.

Researchers from the Faculty of Medicine at Florence University, Italy, writing in the BMJ, claim that Google’s sponsored links are sometimes to web pages that contain worrying medical claims.

The BMJ itself said it had previously run advertisements on through Google’s AdWords service but this had been discontinued after complaints from readers about inappropriate matches between editorial content and advertisements.

The doctors say that in January this year they used Google Italia to search on the key word ‘aloe’. Results generated suggested that aloe could be used as an additional or alternative therapy to chemotherapy. The doctors said showing an advertisement that links aloe and cancer in a response to a query with the single word ‘aloe’ was inappropriate.

They added: “Worse yet is when the website linked to has false medical claims.”

The researchers said Google’s advertising product AdWords enabled advertisers to choose which search words they would like their advertisements to be matched against.

The doctors said Google’s filters should be improved to prevent inappropriate links or Google should not display sponsored links in results of searches on medical terms of products.

They said a further problem was that under the sponsored links section in their search was a short list of ‘related searches’ which linked to other sites stating aloe could cure cancer.

However, Google told E-Health Europe that it has strict terms and conditions about what advertisements are allowed.

A spokesperson added: “We do not allow ads for miracle cures and online pharmacy websites who advertise with us have to be registered with the Royal Pharmaceutical Society of Great Britain. Our processes do a good job of rooting out non-compliant ads and preventing them from showing. If we discover that we are showing ads that break our terms and conditions we will take them down immediately."