A method for treating hyperglycemia and/or reducing serum glucose levels in a patient that includes administering to the patient a therapeutically effective amount of an amine polymer is disclosed. In one embodiment, the amine polymer is aliphatic. Examples of polymers useful in an embodiment of the invention include sevelamer hydrogen chloride and colesevelam. The invention includes the use of amine polymers such as a cross-linked polymer characterized by a repeat unit having the formula: ##STR00001## and salts and copolymers thereof, where n is a positive integer and x is zero or an integer between 1 and about 4. Also described is a use, for the manufacture of a medicament, of a polymer that lowers serum glucose.