ou believe your child may have colic. You quickly run to the computer and log onto an Internet search engine. The search yields 19,660 Web sites about colic. That much information can be overwhelming, but it also gives some physicians pause because so many health sites contain misinformation.

“The biggest problem with the Internet is that there’s no filter on what you read,” says Dr. Bob Bash, director of clinical oncology at Children’s Medical Center of Dallas. “Invariably, I spend the first half of an appointment unlearning what they, the parents, already learned.”

Dr. Ernie Fernandez, a pediatrician in North Dallas who is on the medical staff at Children’s, says using the Internet for health information can be both good and bad.

“Most of the time, the patients get a lot of good information on pediatric illnesses,” he says. “But occasionally, they will find an opinion on the Internet, and so often that makes it difficult for families to make decisions when it comes to treatment options.”

Recently, the University of Michigan Comprehensive Cancer Center conducted an online study of a specific type of cancer. Researchers found that nearly half the Web pages that were analyzed contained treatment information that had not been validated scientifically; 6 percent contained wrong information; and many other sites were misleading.

Dr. Bash says he advises patient families on first consultations to stay off the Internet for at least three or four days to allow the medical staff to educate them first about the disease. He says parents of newly diagnosed children just don’t know enough about the disease yet to know if what they’re reading is true or false.

But there are some helpful sites. Physicians say to look for reputable institutions to search for online health information, such as the American Academy of Pediatrics (www.aap.org) and the National Institutes of Health (www.nih.gov). Many physician groups also are beginning to launch their own sites. The American Medical Association and six other physician groups plan to launch new sites sometime this year.

Dr. Fernandez compares online information with that of a supermarket newsstand. “You can get respected publications or a tabloid. It’s the same on the Internet; search engines don’t differentiate between quality resources,” he says.