The invention provides novel guanylate cyclase-C agonist peptides and their use in the treatment of human diseases including gastrointestinal disorders, inflammation or cancer (e.g., a gastrointestinal cancer), a lipid metabolism disorder, a billary disorder, cardiovascular disease, obesity or an endocrine disorder) by administering at least one agonist of guanalyte cyclase receptor either alone or in combination with a compound typically used to treat the disorder and or with an inhibitor of cGMP-dependent phosphodiesterases.
