Methods for treating colon cancer include administering, to a patient in need thereof, a polymeric proanthocyanidin composition from a Croton species or Calophyllum species in an amount sufficient to treat colon cancer, which composition inhibits COX-2. Methods for treating inflammation locally in the intestines comprise 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.