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Google needs better control of its advertisements and suggested links

BMJ 2009; 338 doi: (Published 18 March 2009) Cite this as: BMJ 2009;338:b1083
  1. Marco Masoni, researcher1,
  2. Maria Renza Guelfi, researcher1,
  3. Gian Franco Gensini, dean2
  1. 1Faculty of Medicine, University of Florence
  2. 2Department of Critical and Surgical Care, University of Florence
  1. Correspondence to: M Masoni m.masoni{at}

    Searching for information is one of the most popular uses of the internet, and medical information is among the types of information that are most sought. Therefore how internet search engines present sources of information to users is important. As the internet is not well policed and regulated, it is up to members of the medical community to be vigilant and to suggest improvements.

    Google, the most popular internet search engine, earns much of its revenue from advertisements related to search terms entered into it. We have noticed that Google’s sponsored links are sometimes to web pages that contain worrying medical claims. On 19 January 2009 we used Google Italia to search on the keyword “aloe.” On the first page of results two sponsored links appeared at the top of the page. The first one said (in Italian): “Aloe vera or arborescens? To purify use aloe [Aloe vera], but in chemotherapy it must be arborescens [Aloe arborescens].”

    Visiting this website, we found the following statement: “The most important use of Aloe arborescens is as an adjuvant treatment with chemotherapy: it is recommended for preparation as a traditional therapy or when other therapies give no results. Aloe is also recommended as a prevention strategy for people predisposed to this type of pathology.” From the same website you can buy a litre of “Aloe Arborescens Superior,” a mixture of extracts from three species of Aloe, for €130 (£120; $170).

    AdWords ( is “Google’s flagship advertising product” and was its “main source of revenue in 2007” ( The software is used by those who want to display advertisements on Google and on its advertising network. Through it users can create advertisements, choose their own key words, and decide which Google queries their advertisements should match. Google decides on placement on its pages of search results: which advertisements to show and in what order.

    But Google’s automated matching to search terms sometimes places inappropriate advertisements. For example Google Guide (which is neither affiliated with nor endorsed by Google), says: “In September of 2003, adjacent to a New York Post article about a gruesome murder in which the victim’s body parts were stashed in a suitcase, Google listed an ad for suitcases. Since that incident, Google has improved its filters and automatically pulls ads from pages with disturbing content” (

    We think that Google’s filters must be improved further. Showing an advertisement that links aloe and cancer in response to a query with only the single keyword “aloe” is inappropriate. Worse yet is when the website linked to has false medical claims. If improving the filter is too complex, it would be better simply not to display sponsored links in results of searches on medical terms or products.

    But there’s a further problem. Appearing immediately under the sponsored links in our search was a short list of “related searches.” Such suggested alternative search terms, which don’t appear on every search in Google, are automatically generated by an algorithm determining terms related to the search that may be useful to refine the query. In our case, the related link “Padre romano zago” connected us to a website ( that contains statements such as: “Cancer can be cured! Padre Romano Zago’s cure, Aloe Arborescens, cured many people’s cancer!” The site has further pages full of statements and “proofs” aiming to show that Aloe arborescens can cure many types of cancer.

    Google has often said that it wishes to enter the healthcare arena in many ways. 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.


    Cite this as: BMJ 2009;338:b1083


    • Editorial note: In the past, has carried advertisements on its pages provided through Google’s AdWords service, but this was discontinued after complaints from readers about inappropriate matches between editorial content and advertisements.

    • See Personal View, BMJ 2009;338:b1080, doi:10.1136/bmj.b1080.

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