Only one rule in medical ethics need concern you — that action on your part which best conserves the interests of your patient.

Fischer reduces medical ethics to a single, patient-centered imperative: choose the course of action that most effectively protects the patient’s welfare. The phrasing suggests a pragmatic, consequentialist stance—ethical deliberation is not primarily about professional etiquette, institutional rules, or the physician’s self-interest, but about outcomes for the person under care. At the same time, “best conserves the interests” implies stewardship and restraint: the clinician must safeguard the patient’s long-term good (health, safety, dignity, and trust), not merely satisfy immediate demands. The quote’s force lies in its simplicity, offering a guiding principle meant to cut through competing pressures and rationalizations in clinical decision-making.