Drug companies' quest for speedy results has led to a boom in trials based in developing countries, where ethical standards may be lax and the impoverished sick abundant. According to the U.S. Department of Health and Human Services Inspector General's office, the number of researchers based outside the United States seeking new drug approvals has increased 16-fold over the last decade. In this article, a 1996 Pfizer trial in Nigeria--the subject of a controversial class-action suit--illustrates the dangers.