The present invention relates to pharmaceutical compositions containing at least one protein active ingredient protected from digestive enzymes. The pharmaceutical compositions contain the at least one protein active ingredient, in free form, as well as, for liquids, a system that buffers them to a pH greater than 4 and less than or equal to 8 or, for solids, a system that exerts, when they are placed in a liquid medium, a buffer effect between a pH greater than 4 and a pH less than or equal to 8.