From a preliminary investigation using alcoholic/aqueous extracts of fresh leaves from various tree species, we observed that pine needle extract carries an extraordinary activity remarkably debilitating the action of trypsin inhibitors(TI) towards trypsin. This finding tempted us to speculate that pine needle tissuses may contain a certain biochemical factor inactivating TI. We are currently conducting a work focussing upon the isolation and characterization of this factor. The tentative results presented here implies that the factor is most likely a small polypeptide which is rather soluble in methanol. The isolation procedure, although it certainly awaits further improvement, and some biochenucal properties of the factor will be discussed. To our knowledge, this protein-like factor which effectively inactivates TI is the first ever found in the field of protein biochemistry.