The present invention provides methods for treating
constipation-predominant irritable bowel syndrome 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 constipation-predominant irritable bowel syndrome
(c-IBS). Treatment of c-IBS includes the treatment of the constipation
component of c-IBS as well as the pain and abdominal discomfort
associated with c-IBS. In one embodiment, the polymeric proanthocyanidin
compound is crofelemer. The present invention in an alternative
embodiment also provides methods for treating alternating
constipation-predominant/diarrhea-predominant irritable bowel syndrome.