The purpose of this study was to determine the effects of altering gastric emptying on postprandial plasma glucose concentration after a physiologic meal in patients with type II diabetes mellitus (T II DM). Nine T II DM patients underwent a double-blind, randomized, three-way crossover study, receiving erythromycin 200 mg, morphine 8 mg, or normal saline (placebo) intravenously prior to ingestion of a radiolabeled, dual-isotope, solid–liquid meal. Gastric emptying of solids and liquids and serial plasma glucose, glucagon, and serum insulin concentrations were measured at baseline and for 5 hr after meal ingestion. Erythromycin accelerated and morphine delayed solid- and liquid-phase gastric emptying compared to placebo (P < 0.05).="" during="" the="" first="" hour,="" the="" postprandial="" plasma="" glucose="" concentrations="" were="" higher="" after="" erythromycin="">P < 0.05)="" and="" lower="" after="" morphine="">P < 0.05)="" compared="" to="" placebo.="" the="" peak="" postprandial="" plasma="" glucose="" concentration="" was="" higher="" after="" erythromycin="">P = 0.05) and lower after morphine (P < 0.05)="" compared="" to="" placebo.="" in="" conclusion,="" pharmacologic="" acceleration="" of="" gastric="" emptying="" resulted="" in="" higher="" postprandial="" glucose="" concentrations,="" while="" delaying="" gastric="" emptying="" resulted="" in="" lower="" postprandial="" glucose="" concentrations="" after="" a="" physiologic="" meal="" in="" t="" ii="" dm.="" these="" results="" suggest="" that="" administration="" of="" opiate="" analgesics="" or="" prokinetic="" agents="" to="" diabetic="" patients="" may="" alter="" glucose="" control.="" modifying="" gastric="" emptying="" may="" be="" helpful="" in="" achieving="" glucose="" control="" in="" t="" ii="">