For the public opinion, medical strikes are a controversial issue; physician's ethical judgments are also different. The present article analyses the requisites to consider legitimate a strike and, based on these, the ethical duties of physicians; the features of medical unionism; the ethical duties of authority; the manipulation of ill people by the strike and the social factors that may cause these conflicts. In a medical strike, universal ethical values based on the Hyppocratic oath and promoted by the profession, are endangered. This article concludes that a medical strike may be explainable due to different reasons, but it is not ethically justifiable beyond any doubt. The health profession that is not prepared to give up strikes as gremial pressure tool, should not choose a profession that takes care of the ill. The best way to avoid medical strike is to prevent them: the society and the authority have the ethical obligation to create work conditions that elude conflicts. To settle disputes between physicians and health institutions, the creation of a permanent arbitral instance agreed by physicians and the authority, i.e. a high level committee integrated by respected individuals and physicians, could be necessary. This committee should send forth veredicts that would be obeyed by the contending parties.