The ability of Acarbose to improve the metabolic control of type II diabetics has been studied in a double blind study. 28 patients, poorly controlled despite maximal oral treatment and diet received 4 months of Acarbose (n = 15) or Placebo (n = 13). After 4 months of Acarbose post prandial blood glucose levels were significantly reduced at 10 and 14 hours compared to baseline values (p less than 0.05). Nevertheless, the metabolic control of Acarbose and Placebo groups was not statistically different at the end of the study. The beneficial effect of Acarbose appears to be slight but this may be due to 1) the relatively low dosage of acarbose used, 2) the importance of carbohydrate restriction, or, more probably, 3) the selection of the patients as most of them might have been classified as insulin requiring diabetics.