The famous and oft-quoted maxim "Do no harm" should not be thought of as the first principle of medical ethics. The documents of the Hippocratic tradition and clinical experience indicate that a more appropriate and helpful first principle would be "Above all, be useful." The concept of usefulness implicitly rests at the very heart of medicine itself and the physician-patient relationship. The failure to adhere to this concept undermines the physician-patient relationship, dissolves the distinction between quacks and physicians, and destroys the integrity of the medical profession. The determination of useful medical treatment belongs to both physicians and patients. Any decision to initiate, continue, or discontinue diagnostic or therapeutic action has both a medical and a personal value component; the former properly belongs to physicians and the latter to patients. Practicing medicine with the intent of producing benefit and being useful to the patient is far more fundamental than practicing medicine to avoid harm.