Googling a cure for chest pain might put your personal information more at risk than you think, according to new research by Tim Libert of the Annenberg School for Communication.

Libert, a doctoral student who specializes in computer security and Internet governance, looked at a little-known side effect of health-related Web searches: the amount of private health information divulged to third parties, like advertisers and data brokers, when people investigate their medical concerns online.

“I took the names of about 2,000 common diseases or treatments and I found the top 50 search results for each of those, so that gave me about 80,000 Web pages,” Libert explains. He found that “about 90 percent” of them collect and distribute personal information to outside parties.