Abstract: A method for the detection of bioactive peptides derived from a precursor protein or protein-containing biological extract, comprising the steps of: (i) providing a library of peptides derived from said precursor protein or protein-containing biological extract; (ii) optionally screening said library to confirm that it includes peptides exhibiting one or more biological activities; (iii) separating said library to provide fractions of the library; (iv) screening said fractions to identify active fractions which include peptides exhibiting said one or more biological activities; (v) optionally separating each said active fraction to provide sub-fractions thereof, and screening said sub-fractions to identify active sub-fractions which include peptides exhibiting said one or more biological activities; and (vi) isolating from said active fractions or active sub-fractions one or more peptides exhibiting said one or more biological activities.