Among realms being dealt with by sunna in general and prophetic sunna in particular is medicine and hygiene of body and psych. It is attempted in this essay to answer some questions posed concerning authenticity of those hadiths, such as: Considering their source and chain of transmission, at which level of validity do medical hadiths stand? Assuming validity of their source and authenticity of their chain of transmission, what is the criterion for their validity? In other words, should such hadiths be accepted devotionally like juristic hadiths, or should they be accepted only if they are proved by definite, certain achievements of science? Generally speaking, can such realms as medicine and hygiene be included in the scope of religion and prophecy of the holy prophet? May the religious realm be defined through consideration of medical hadiths? And the like.