Adverse drug reactions have reached epidemic proportions, killing more people each year than die on the nation's highways, and doing serious damage to millions more. This problem has taken on special significance recently: The FDA has pulled 10 drugs off the market in the past three years for safety reasons, which is unprecedented in the agency's history. Nearly 20 million patients, almost 10% of the U.S. population, were estimated to have been exposed to these drugs before their removal. Few people, however, are aware that their medications could be harmful, or know how to spot the warning signs and what to do if they suspect there's a problem. Yet a 1998 University of Toronto study found that roughly 100,000 Americans die of adverse drug reactions each year, and 2.1 million more are hospitalized. The FDA received reports of more than 258,000 adverse drug events in 1999, nearly quadruple the 68,000 incidents reported a decade earlier. And FDA officials acknowledge that they're catching only a tiny fraction of these incidents. More new therapies are being sold first in the United States, rather than in Europe and Asia. In the early 1980s, only 2% to 3% of new drugs were introduced in the United States. By 1998, that number climbed to more than 60%, according to FDA officials, largely due to faster approvals by the agency. Aggressive marketing of new drugs can exacerbate the problem by persuading doctors and patients to seek out the latest therapies more quickly. And it's not just newer drugs that can be dangerous.