The sanctity of the medical profession in our society is rooted in both religious teachings and rich Iranian culture. For this reason, in Islamic jurisprudence, the subject of medicine and Iatrology has been the subject of extensive technical and legal discussions as a separate chapter. On the other hand, the principle of good faith and mutual trust in the doctor-patient relationship requires both parties by respecting their agreement, do not refuse to fulfill their obligations without a valid excuse. The main question is to what extent the good faith is based on the responsibility of the doctor. It is affect? In this article, with a comparative study of the French legal system and jurisprudential sources, while examining the theories related to the relationship between the doctor's responsibility and the intention of beneficence and good faith, it was concluded that the existence of good faith is both effective and also is regarded as a factor to reduce the amount of damage which is compensable.