The effect of two alpha - glucosidase inhibitors, acarbose and miglitol, on postprandial glucose levels following wheat and potato starch loading was evaluated in sand rats with resultant dramatically reduced postprandial glucose levels. The inhibitory effect on starch digestion was dose concentration-dependent. Eighty-six and 72% inhibition was reached with 1 mg of miglitol and acarbose, respectively. Daily plasma glucose profiles and cataract formation were determined following long-term feeding with a diet containing acarbose and miglitol. Both drugs led to a significant reduction in glucose levels, acarbose being more potent, possibly via inhibition and delay of carbohydrate digestion. Acarbose caused a marked decrease in cataract incidence; the mechanism for this effect requires more elucidation. Since acarbose delayed and possibly prevented cataract formation in sand rats, we support the concept of its use as an adjuvant in the treatment of diabetic patients.