The Clinton administration will announce a new initiative today aimed at cracking down on illegal sales of prescription drugs over the Internet that for the first time would require all Web sites that dispense medicine to be regulated by the federal government.

The plan would allow the Food and Drug Administration to start verifying the quality of hundreds of online companies that have sprung up in the last year, allowing consumers to fill prescriptions without going to a traditional drugstore.

If approved by Congress, the administration's proposal also would create federal fines of as much as $500,000 for Web sites that sell drugs without first obtaining a valid prescription from the online buyer and would expand the FDA's powers to investigate sites that are suspected of operating fraudulently.

The initiative represents the government's first attempt to harness this new industry that is allowing consumers to obtain medicine in a convenient new manner but that also has the potential to harm patients who order drugs through unscrupulous operators.

According to administration officials, the proposal will be part of the 2001 budget request that President Clinton is to submit to Congress next month--and is one of the first aspects of that budget that the White House has disclosed. In addition to seeking congressional approval to broaden the FDA's authority and to impose the new civil penalties, the White House also will seek $10 million for what FDA Commissioner Jane Henney yesterday called a "first investment" to acquire the staff and technology necessary to help root out illegal online sales.

Even though pharmacies in general are licensed by states and are exempt from FDA regulation, Henney said the administration would like to begin requiring the pharmaceutical Web sites to be certified by the federal government. As part of that process, states or independent entities would inspect each site to, among other things, make sure that it had a state license and to monitor the pharmacists and physicians who work for the site.

In describing the steps the administration wants to take, Henney was careful to emphasize that the recent proliferation of companies selling drugs via computer has many advantages for patients, especially those who are disabled, live far from traditional pharmacies or simply are too sick to go out. But she said, "we are trying to sort out the bad actors."

Although it is evident that new Web sites selling medicine are coming into existence each week, no one knows how many consumers are buying medication from them. Nor is it clear how many have received drugs that were contaminated or not approved for use in this country--or how many have sold drugs without first being shown a prescription.

Anecdotally, evidence is starting to surface that the largely unregulated world of online drug sales can sometimes prove dangerous, particularly since consumers often have little way to discern reputable companies from fly-by-night operators.

Patients and government regulators at a House Commerce Committee hearing last summer both extolled the convenience of ordering medicine electronically and described how slippery this new industry can be. For instance, Web sites do not always bother to get pharmacy licenses in every state in which their customers live--and the most fraudulent sites sometimes vanish and resurface under a different name before regulators can step in to investigate a complaint.

These "virtual pharmacies," when they are reputable, are similar to mail-order pharmaceutical companies. Patients send in prescriptions from their doctors, and the companies mail the medicine to patients' homes.

Jeffrey Shuren, medical officer of the FDA's Office of Policy, said yesterday the agency is investigating hundreds of reports of Web sites that write prescriptions and dispense drugs solely based on a written questionnaire that consumers fill out. The patient does not necessarily have to visit a doctor in person to make sure they need the drug they want and can use it safely.

Other Web sites, Shuren said, sell drugs that are not approved for use in the United States. The FDA recently took action against a company, Lane Labs, that was selling shark cartilage as a cancer cure, even though the National Institutes of Health are only beginning to explore whether the substance has any benefit as a cancer therapy. Other companies mislabel drugs, and reports have surfaced in other countries--though not in the United States--of Web sites that have dispensed fake versions of Viagra, the popular treatment for impotence.

Confronted with proliferating online sales, a pharmacy trade group has encouraged Web sites to meet a set of quality standards. But the FDA's Henney said that private effort does not go far enough because it is voluntary.