RESUMEN
Because of the uniqueness and complexity of medical facilities that provide medical care,even people who sincerely agree to principles of medical ethics would consciously fall away from certain principle of medical ethics. Although such deviation is mere expedient, enormous impact is imposed on the principles of medical ethics. Contingency in moral choices, being an expedient under specific circumstances, is inherently necessary and justifiable. However, temporary deviation does not negate a principle. When there are conflicts of principles, contingency in medical moral choices requires that the moral values of different medical behaviors be judged and choices be made. Appropriate contingency in medical moral choices depends on the rational beliefs of medical staff and the right judgment about moral values of different medical plans.