A method for prophylactically treating irritable bowel syndrome in a mammal through the administration of a zinc carnosine composition like zinc carnosine is provided, although other forms of zinc carnosine or other components exhibiting zinc carnosine activity like other metal carnosine complexes may be used. The effective amount of composition to be used will depend upon such factors as the age and weight of the mammal, and whether treatment of existing IBS symptoms, or prevention of the onset of IBS symptoms is desired. A complex comprising such a zinc carnosine composition for prophylactically treating IBS in a mammal is also provided.