The Authors, after considering post-operatory sepsis as cause of failures and as an important economic damage, make among them a distinction according to the arising area and to the seriousness of their manifestations. They, later, describe corrective and prophylactic measures which in colo-rectal surgery ase campulsory assumptions for sepsis prevention. After relating their experience, Authors reaffirm short-term protocol validity and point out validity of alternation of large spectrum molecules in order to avoid possible arising of bacterial resistances.