In the Internet age, the "doctor" is in 24/7, and that is not always a good thing.

About 75 percent of Internet users regularly search for health information online, according to Pew Internet Project. While some are looking for information on a specific disease or condition, many are trying to get a diagnosis of what ails them by typing in their symptoms on a search engine such as Google. But the results they get may be misleading, overwhelming or simply wrong.

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"Don't Google a symptom," warns Dr. Mark Graber, president of the Society to Improve Diagnosis in Medicine, former chief of medicine at the Northport VA Medical Center and professor emeritus of medicine at Stony Brook University. "Even if it does have your diagnosis, it's going to give it to you with 1,000 different things in no particular order."

Google is best used after you receive a diagnosis from your doctor, Graber says. "We need to make a distinction between going online to figure out your diagnosis and going online to find out more about what you actually have," he says. For example, Googling a vague symptom such as "lightheadedness" results in vague results. But Googling a condition such as "hypertension" gives you immediate and useful information on symptoms and treatment.

Graber says there are dedicated online symptom checkers that are much better at giving you a diagnosis than Google. "The very best is one called Isabel," he says. Isabel, which started as a diagnostic system for health care professionals, operates a free patient-focused version at nwsdy.li/isabel. "It also makes suggestions about whether this is something you can watch for awhile or whether you really need to go to the emergency room," Graber says.

You also have to carefully choose the sites where you get your health information. Some are loaded with errors, false information or unsupported opinions. Among the sites Graber says offer reputable information are webmd.com and medscape.com. Government-run sites cdc.gov and nih.gov also have trustworthy information. For a list of the "Top 100 Health websites You Can Trust" compiled by the Medical Library Association, go to nwsdy.li/healthsites.

What do you do with all this health information? More and more, patients print it out and bring it to their physician. But even a doctor with the kindest bedside manner may have a grouchy desk-side manner if a patient whips out reams of papers. "I would hope their physicians would be receptive to discussing those kinds of things," Graber says. "Many are, and some aren't."