Pharmaceutical compositions containing a proanthocyanidin polymer composition which are useful for the treatment and prevention of secretory diarrhea are provided. The invention specifically relates to pharmaceutical formulations of a proanthocyanidin polymer composition which has been isolated from a Croton spp. or a Calophyllum spp. In particular, the invention relates to a formulation of a proanthocyanidin polymer composition which protects the composition from the effects of stomach acid after oral administration, particularly to those formulations which are enteric coated. The invention also relates to methods of producing a directly compressible proanthocyanidin polymer composition, as well as compositions containing the directly compressible proanthocyanidin polymer composition.