The present invention provides oral pharmaceutical compositions that enable the successful delivery of drugs in a pharmaceutically effective amount, particularly poly (amino acids) such as peptides, peptidomimetics and proteins. e.g. hormones to a subject via oral administration to accomplish the desired therapeutic effect. The oral pharmaceutical composition comprising a poly (amino acid) as the active ingredient, e.g. a peptide or protein, shows a rapid disintegration and/or dissolution such that the active ingredient is able to attain a therapeutic effect.