You have a strange tingling sensation in your toes. Immediately, you log on to the Web and find your favorite medical information site. Your heart begins to pound as you consider your condition: You might have multiple sclerosis, a brain tumor or perhaps both. Most likely, though, you are suffering from "cyberchondria," the term for a new condition that leads people to attempt self-diagnosis obsessively using the Web. "If you are a hypochondriac, then clearly the Internet extends your ability to be neurotic," says Dr. Paul Cundy, a London general practitioner and chair of the Information Management Technology subcommittee of the General Practitioners Committee of the British Medical Association. To make matters worse, medical information on the Web can be incomplete or misleading. Last year, the survey found, 100 million Americans went online in search of health information, and 70 percent of them said they took the information seriously when considering treatment, according to Sam Karp, CIO for the California HealthCare Foundation, a private institution in Oakland, Calif. But a recent study funded by the foundation and published in May\u2019s issue of The Journal of the American Medical Association found that while many English-language sites contain accurate information, Web surfers can easily be led astray. For example, a childhood asthma website reports on one page that using inhaled steroids does not stunt growth in children but another page says that it can. In order to avoid confusion or anxiety related to the Web, the report recommends that surfers look at several sites instead of relying on information from just one. And most important, patients should discuss the information they find on the Web with a health-care provider before using it to make any decisions about treatment. The good news is that so far true cyberchondriacs are rare, Cundy reports. "Hundreds of my patients have consulted the Web before coming to see me," Cundy says. "But many of them do have a healthy skepticism. I don\u2019t think the Internet can turn normal people into neurotics."