醫療行爲在刑法上一直被評價爲傷害行爲的一種。醫療行爲正當性與適法性的基礎，刑法學說常以現行刑法第22條「業務上之正當行爲，不罰」做爲論述論據。至於「業務上正當行爲」此一阻卻違法事由的要件與運用，學說上則是少有探討，實務上也乏見相關判決。最常見者，乃是參考日本學說見解，且每每論及業務上正當行爲時，即舉醫療行爲作爲典型事例。但另一方面，刑法學說在探討醫療行爲正當性的要件時，亦有主張揚棄業務上正當行爲概念，採取德國學說見解，以「得被害人承諾」此一超法規阻卻違法事由來阻卻違法。此一看法隨著醫療領域中「告知後同意」原則的確定，其立論則是愈行堅實，且日益廣泛爲醫學界與法律界所認同。 作爲法律繼受國的我國，對於醫療行爲正當性的看法，學說見解常在 德、日學說爭論之間擺盪，且因德、日見解之不同而存在著分歧意見。本文嘗試整合德國與日本學說，並針對我國刑法條文之不同規定，發展出以「告知後同意」結合「業務上正當行爲」概念的論述模式。這樣的論述雖非新穎，但亦希望能藉此文提供我國刑法學界與實務界對醫療行爲之正當性事由較爲合理且統一的看法。

Medical treatment is always evaluated as a sort of injury in criminal law. Some scholars are of the opinion that paragraph 22 of Taiwan's Criminal Code ”the proper behavior of occupation shall not be punished” accounts for its lawfulness. In terms of this justification ground, there are few discussions about it in current criminal law theories, apart from the explanations with the example of medical treatment based on Japanese doctrine. Other scholars consider to follow the German doctrine that it could be justified by the victim's consent which goes beyond positive provisions of Criminal Code. This opinion is more persuasive and generally accepted by the medical and criminal law community along with the recognition of principle ”informed consent” in medicine. Both of the justification grounds for medical treatment are respectively held by Japanese and German criminal doctrines. In Taiwan, due to different opinions about following German or Japanese doctrines, which ground can justify the medical treatment is still in dispute. Considering the different provision in Taiwan’s Criminal Code from Germany's and Japan's, this article tries integrating both foreign doctrines to develop a new argument that a proper behavior of occupation ought to be based on informed consent. Although this argument is far from novel, it is expected to provide the medical and criminal law community a more reasonable thought upon the justification ground of medical treatment.