The doctors who run clinical trials of experimental drugs and devices have one of the most ethically sensitive jobs in health care. They are guiding patients into unknown territory, away from the established standards of care, to test treatments that may or may not work, and may have unexpected side effects. One would hope that those recruited would be at the very top of their profession. But by cross-referencing the Food and Drug Administration’s (incomplete) records of clinical investigators against records of medical discipline in the four largest states, I found dozens of doctors selected to work on clinical trials over the past five years who had previously been censured for problems with patient care. Some had made mistakes that left patients dead or maimed; others were themselves addicted to narcotics. Through some disturbing examples, the article explored the how the minimal screening employed by some drug companies and clinical trials firms, including some of the largest in the business, allows doctors with such records to be hired.