Clinical trials are crucial in determining whether novel medical interventions are effective and safe. The use of human participants in such trials is also vital, as animal testing and computer simulation are no substitutes for testing people. Regulation aimed to ensure ethical and safe practices when using human participants, had its beginnings at a global level in response to World War II atrocities. Since that time, there has been an exponential rise of clinical trials, driven mostly by large pharmaceutical companies and for-profit contract research organisations motivated to find preventions and cures for illness and disease, and profit. In turn, there is an ever-growing demand for clinical trial human participants. This article considers historical and contemporary instances of when such trials have gone wrong, and examines the development, and importance of comprehensive, robust, and responsive regulation and governance of clinical trials at both international and domestic levels of which researchers must be aware.