Quick clicks to health: the World Wide Web, with more than 20,000-plus health sites, may seem like a wild, wild world. So how do you avoid pitfalls—misleading and biased information, charlatans, quacks, and such? Get started with this sampling of proven Internet addresses

Healthfinder, sponsored by the U.S. Department of Health and Human Services, is a gateway to more than 1,800 agencies and organizations. Using a health gateway is often the best first step in a search, say experts. Healthfinder will direct you to preselected, targeted sites, unlike general search engines that do not always produce relevant results. If you're a novice Web surfer, explore the site's databases and guides to common health matters, and the hot topics in the Health News section.

www.medlineplus.gov

The National Library of Medicine, the world's largest medical library, developed this site, where you can access information about more than 400 diseases and conditions, a guide to pharmaceutical drugs, links to National Institutes of Health clearinghouses, and other helpful resources.

www.cdc.gov

Stop here for news about threatening diseases, traveler's health, immunizations, bicycle safety, dog bites, foodborne illnesses, AIDS, sexually transmitted diseases, and more. M.J. Tooey, deputy director of the Health Sciences/Human Services Library at the University of Maryland, enjoys the Hoaxes and Rumors section, which debunks myths and corrects misinformation.The Harvard School of Medicine stores an array of carefully reviewed, reliable materials here for all to see. For example, search for information on "stroke" and you will receive basic fact sheets, numerous feature articles, news reports, and a diary to help keep track of your blood pressure. Two site programs can be especially useful. Symptom Scout asks questions about symptoms and offers clues for diagnosis. TopicDoc searches MEDLINE, which has a database of 11 million articles, to target the most promising studies. The University of Pennsylvania School of Dental Medicine also oversees a large body of material about dental health and periodontal disease.

www.mayoclinic.com

Click on this site, affiliated with the well-known Mayo Clinic, and you feel at ease with the organized layout. Chock-full of in-depth articles, the editorial content also makes you feel secure. The site offers an index of diseases listed A-Z, 11 Condition Centers (Alzheimer's, for example), and eight Healthy Living Centers (such as Women's Health). If you're faced with various medical tests and treatments, consult the Health Decisions Guide section, which walks you through options. Do note, however, that the slant on information is potentially limiting, since Mayo Clinic specialists provide most of the content.

www.medem.com

The American Medical Association, along with six other physician specialty groups, founded this site. Other specialty groups and state medical societies now contribute information. You'll find straightforward, peer-reviewed articles on common ailments. However, the library's rare conditions section may disappoint. "The library has good, credible information, but it's not research-oriented," says M.J. Tooey. "If I were interested in lung cancer, I'd get an overview here, then go to a cancer-specific site to answer more complex questions."

www.cbshealthwatch.com

This site is the consumer-health version of Medscape, a company that publishes medical information for healthcare professionals. It carries original articles produced by staffs at CBS and Medscape. You'll find information categorized in three sections: Diseases and Conditions, Family Health, and Healthy Lifestyle. The site contains write-ups on common conditions, pharmaceutical drugs, and medical tests.

www.webmd.com

WebMD is part of an ambitious project by a national health-care company to link patients, physicians, hospitals, and health insurers in an electronic health network. It has experienced cutbacks but remains heavily used. The Disease and Conditions section helps you zero in on a specific health problem. Search topics by three different interests: Health and Wellness, Newly Diagnosed, and Living with Illness. But keep your eyes wide open when reading "sponsored" sections, since commercial pressures may slant information.

www.4women.gov

Part health encyclopedia, part women's advocate, this National Women's Health Information Center site draws on thousands of publications from a federal clearinghouse. It also has valuable special-category sections, such as minority health, women with disabilities, and a roundup of men's health materials.

www.kidshealth.org

Physicians from the Nemours Foundation, a group that operates children's hospitals and specialty centers in Florida and Delaware, are the driving force behind this comprehensive library of health articles.

www.mentalhelp.net

This comprehensive guide offers more than 40 Issues and Disorders Centers and more than 25 Information Centers (such as Child and Adolescent Development, and Marriage and Family Therapy). Other related sites: National Mental Health Association (www.nmha.org), American Psychological Association (www.apa.org), and National Institute of Mental Health (www.nimh.nih.gov).

A network of medical librarians can assist you with your questions about medical and health Web sites, says Jean Shipman, secretary of the Medical Library Association Board, and director of the Tompkins-McCaw Library, Virginia Commonwealth University. She suggests contacting the National Library of Medicine at 800/338-7657 or www.nnlm.gov.

HOW TO TRUST A SITE

Tom Ferguson, M.D., who "The Ferguson Report," an electronic newsletter for health-care professionals, believes most Internet users try to gather information wisely and check it out with their doctors. Even if you're just getting started, you too can become a Web-savvy consumer by asking these questions:

* Who is the site's sponsor or owner? Many sites are backed by companies whose primary purpose is to publicize or sell medications, products, or devices. Others are special-interest groups eager to promote an agenda. The About Us section will reveal the publisher and mission.

* Is the information credible? Who provides it, and what are their credentials? Is it based on scientific findings?

* Is the information timely? For the latest medical tests, technology, and treatment options, you need current information, with dates posted when revisions were made.

* Does the site state its ethics, advertising, and privacy policies? Look for organizations with the "HON" seal, a promise to maintain conduct standards set by the Health on the Net Foundation. Many top Web sites have formed Hi-Ethics, an alliance to develop guidelines and an accreditation program for sites. The American Accreditation HealthCare Commission makes these standards verifiable through its Health Web Site Accreditation Program (www.urac.org), says Donald Kemper, chief executive of Healthwise, Inc., a not-for-profit information center.

* Does the site peddle "miracle" cures? The nonprofit site www.quackwatch.com reveals health frauds and myths.

* Are you reviewing information at various sites, not just one? Kaiser Permanente sponsors The Health Information Check Up (www.kp.org/hicheckup), which can help you judge reliability.