You wouldn’t think the cities had much in common. Iaşi, with a population of 320,000, lies in the Moldavian region of Romania. Mégrine is a town of 24,000 in northern Tunisia, on the Mediterranean Sea. Tartu, Estonia, with a population of 100,000, is the oldest city in the Baltic States; it is sometimes called “the Athens on the Emajõgi.” Shenyang, in northeastern China, is a major industrial center and transportation hub with a population of 7.2 million.

These places are not on anyone’s Top 10 list of travel destinations. But the advance scouts of the pharmaceutical industry have visited all of them, and scores of similar cities and towns, large and small, in far-flung corners of the planet. They have gone there to find people willing to undergo clinical trials for new drugs, and thereby help persuade the U.S. Food and Drug Administration to declare the drugs safe and effective for Americans. It’s the next big step in globalization, and there’s good reason to wish that it weren’t.

Once upon a time, the drugs Americans took to treat chronic diseases, clear up infections, improve their state of mind, and enhance their sexual vitality were tested primarily either in the United States (the vast majority of cases) or in Europe. No longer. As recently as 1990, according to the inspector general of the Department of Health and Human Services, a mere 271 trials were being conducted in foreign countries of drugs intended for American use. By 2008, the number had risen to 6,485—an increase of more than 2,000 percent. A database being compiled by the National Institutes of Health has identified 58,788 such trials in 173 countries outside the United States since 2000. In 2008 alone, according to the inspector general’s report, 80 percent of the applications submitted to the F.D.A. for new drugs contained data from foreign clinical trials. Increasingly, companies are doing 100 percent of their testing offshore. The inspector general found that the 20 largest U.S.-based pharmaceutical companies now conducted “one-third of their clinical trials exclusively at foreign sites.” All of this is taking place when more drugs than ever—some 2,900 different drugs for some 4,600 different conditions—are undergoing clinical testing and vying to come to market.

Some medical researchers question whether the results of clinical trials conducted in certain other countries are relevant to Americans in the first place. They point out that people in impoverished parts of the world, for a variety of reasons, may metabolize drugs differently from the way Americans do. They note that the prevailing diseases in other countries, such as malaria and tuberculosis, can skew the outcome of clinical trials. But from the point of view of the drug companies, it’s easy to see why moving clinical trials overseas is so appealing. For one thing, it’s cheaper to run trials in places where the local population survives on only a few dollars a day. It’s also easier to recruit patients, who often believe they are being treated for a disease rather than, as may be the case, just getting a placebo as part of an experiment. And it’s easier to find what the industry calls “drug-naïve” patients: people who are not being treated for any disease and are not currently taking any drugs, and indeed may never have taken any—the sort of people who will almost certainly yield better test results. (For some subjects overseas, participation in a clinical trial may be their first significant exposure to a doctor.) Regulations in many foreign countries are also less stringent, if there are any regulations at all. The risk of litigation is negligible, in some places nonexistent. Ethical concerns are a figure of speech. Finally—a significant plus for the drug companies—the F.D.A. does so little monitoring that the companies can pretty much do and say what they want.