Twenty-two patients with normal carbohydrate metabolism and 16 diabetic patients, all 38 having peripheral occlusive arterial disease, took part in an investigation into the effect of pentoxifylline on blood glucose and serum insulin following an oral glucose tolerance test (OGTT). Pentoxifylline was administered by the i.v. route and the investigation took the form of an acute study (200 mg) and a 14-day chronic study (400 mg). Neither acute nor chronic medication elicited any change in blood glucose or serum insulin. Pentoxifylline does not affect blood glucose.