Background The standards of professional practice are constantly shifting to keep pace with acquired knowledge. When the standards fell short of professional expectations, when the practising physician became more concerned with financial gain than effective patient care, society needed a reformer to evaluate the process and to improve it. Study Design Individual physicians and scientists were selected from throughout the history of medicine until the end of the 18th century, who conformed to our definition of reformers, namely, a person who changed the structure or ideology of medical practice. Results This survey demonstrates that reforms are produced by persons whose minds possess analytical quality and critical judgment. Reformers have influenced the directions of medical practice and teaching. Conclusion The improvement in medical practice has been achieved through intuitive leaps, rejection of conventional practice, painstaking research or administrative restructuring.