An oral hypoglycemic drug (Diabinese-chlorpropamide) was given inadvertently to a nondiabetic with renal insufficiency instead of the prescribed phosphate binder (Dialume-aluminum hydroxide). It was determined from this situation that hemodialysis is of no benefit in removing the drug from serum; the hypoglycemic effect of chlorpropamide is profound in nondiabetics, and the duration of therapy with dextrose infusions can be quite prolonged. We provide recommendations regarding therapy, bedside glucose monitoring, and prevention.