The present invention is directed to methods for treating diarrhea, both chronic or acute forms, by the administration of a therapeutically or prophylactically effective amount of antibodies and fragments thereof having binding specificity for CGRP. In particular the methods prevent or reduce diarrhea in conditions or treatments resulting in elevated CGRP levels, e.g., in the GI tract (colon) that are associated with diarrhea and/or improper electrolyte and fluid excretion from the bowel or urinary system. More specifically, this invention relates to treatments using the anti-CGRP antibodies and fragments described herein, and binding fragments thereof.