Each year millions more Americans consult medical sites on the Internet to learn more about their maladies and preventive measures before calling a doctor. Medical experts say the process is changing how medicine is being practiced in a manner more profound than any change since the advent of managed care.

• In 1996, 7.8 million U.S. adults retrieved health information from the Internet -- a figure which grew to more than 22 million for 1998, and is projected at 33.5 million in 2000.

• According to the research firm Cyber Dialogue, the most common medical search is for information about a specific disease.

• The most common ailments researched, according to a recent Harris Poll, are depression, allergies or sinus problems, cancer, bipolar disorder, arthritis and high blood pressure.

• Next, people seek diet and nutrition advice, followed by information about pharmaceutical drugs and women's health.

Experts say the Internet consumer health market will become a $1.7 billion business by 2003.

There are a number of important implications. One is that information available on some sites is just plain wrong -- which frightens doctors and should alert their patients to operate with extreme caution.

Another is that the wealth of Internet medical information is altering the doctor-patient relationship. "Every doctor needs to be prepared for the day when somebody comes in with more information that we don't know about," warns J. Sybil Biermann, a surgeon at the University of Michigan. "We need to be prepared and accept that and learn from our patients. It's a new idea of how things should go in the typical medical model," she adds.

Source: Robert Davis and Leslie Miller, "Net Empowering Patients," USA Today, July 14, 1999.