San Francisco - Flu is far from the only sickness making the rounds this time of year. Millions of people are also at risk from "cyberchondria," according to a report released Tuesday by a pair of Microsoft researchers.

The threat comes from the growing number of people who dash to the internet as soon as they feel an unusual twinge, pain or anything else that could be a symptom of sickness.

The study found that web searches for such common terms as "headache" or "chest pains" were likely to lead people to pages describing serious conditions - even if more benign conditions were likelier explanations. For example, there were just as many results that linked headaches with brain tumour as with caffeine withdrawal even though the latter explanation is far more likely to be correct.

The researchers said they undertook the study as part of an effort to improve Microsoft's search service. The study examined the results of searches on health-related web sites and also quizzed more than 500 Microsoft employees about the results of their health-related searches.

The survey also found that more than half those who conduct medical searches said that results related to a serious illness has interrupted their day-to-day activities and caused anxiety.

Research author Eric Horvitz said that the problem was exacerbated by the tendency of users to focus on the first few search results, and drill down if any of them indicated the possibility of serious illness.

"People tend to look at just the first couple results," Horvitz told the New York Times. "If they find 'brain tumour' or 'ALS,' that's their launching point." (dpa)