We all know there's an staggering amount of medical information on the Web. The problem is much of it is bogus, designed to sell you something or just unreliable.

The editors at Good Housekeeping found that in some causes you could harm your health by relying on medical information from Wikipedia.

When you go online for prescription drug information, Wikipedia is often the first link that pops up. It's a free encyclopedia with content written and edited by users. But on Wikipedia, there could be serious omissions.

Pharmacists from Nova Southeastern University looked up answers to 80 drug-related questions on Wikipedia and compared them to Medscape drug reference, a free and professional site where changes are thoroughly reviewed.

"And what they found was that while Wikipedia wasn't wrong on anything, they didn't get answers to 60 percent of their questions. On Medscape it was only 17 and a half percent," said Toni Hope, health director of the Good Housekeeping Research Institute.

How do you know if you're on a dependable medical Web site?

"In order for a person to know a really good Web site, one of things I always tell them to look for is the HONcode, and you can find that at the bottom of the Web site. You can really usually be pretty sure the information is good there," said Pat Regenberg, medical librarian at Atlantic Health Services.

For reliable drug coverage, go to Medlineplus.gov. The site is run by the National Institute of Health and the National Library of Medicine.

Bottom line: if you use the the Internet for drug information, Wikipedia should not be the only site you visit.

Be aware that negative side effects may be missing on Wikipedia. A consumer watchdog group found that people with access to drug companies' computers have deleted negative information about some products. While information was quickly restored, it's still dangerous if the page has missing information.