The present invention provides methods for preventing colon cancer by administering, to a patient in need thereof, a polymeric proanthocyanidin composition from a Croton species or Calophyllum species in an amount sufficient to prevent colon cancer, which composition inhibits COX-2. The present invention also provides methods for treating inflammation locally in the intestines comprising administering to a patient in need thereof, a polymeric proanthocyanidin composition from a Croton species or Calophyllum species in an amount sufficient to treat inflammation. In one embodiment, the polymeric proanthocyanidin compound is crofelemer. The present invention in alternative embodiments provides methods for treating pain locally in the intestines and treating inflammatory bowel diseases, such as Crohn's disease and ulcerative colitis, as well as for treating familial adenomatous polyposis (FAP).