The effect of the alpha-glucosidase inhibitor Acarbose on collagen fluorescence reflecting formation of advanced glycation end products was examined in streptozotocin-diabetic rats. 2. Treatment with Acarbose for eight weeks after induction of diabetes prevented the increased fluorescence in skin and tail tendon collagen associated with untreated diabetes. 3. Acarbose improves integrated glycemic control and beneficially influences the consequences of excess glycation in long-lived connective tissue proteins.