HPLC on a reversed phase column, amino acid sequencing and mass spectrometry were used to determine the structure of two human gingival crevicular exudate oligopeptides (Leu‐Thr‐Pro‐Glu‐Glu‐Lys‐Ser‐Ala‐Val‐Thr‐Ala‐Leu and Leu‐Val‐Val‐Tyr‐Pro‐Trp‐Thr‐Gln‐Arg‐Phe) which were shown to have been derived from the β‐chain of hemoglobin. These sequences may simply represent two degradation products of the β‐chain. However, their preservation in an exudate characterized by active peptidolysis may also prompt the que