Ischemia is thought to be a major component in the pathogenesis of foot problems. The authors use the Xe-133 washout method to evaluate the blood perfusion of muscle tissue in the lower legs of patients with noninsulin-dependent diabetes mellitus (NIDDM). Eighty-five male patients with NIDDM ranging in age from 51 years to 79 years (mean, 66.5 years) and 47 nondiabetic control males with a matched age ranging from 52 years to 82 years (mean, 64.5 years) were included in this study. None of the diabetics had a history or presentation of peripheral vascular disease in the lower limbs. The patients were separated into groups according to the duration of the disease and condition of blood sugar control. The Xe-133 washout method was performed in the anterior tibial muscle of all the subjects. According to a Student's t-test, the tissue perfusion were of significant difference between 1) NIDDM and normal controls (1.98 +/- 1.39 ml/100 g/minute versus 2.85 +/- 1.35 ml/100 g/minute), 2) good and poor blood sugar control (2.36 +/- 1.58 versus 1.51 +/- 0.94), and 3) long and short disease durations (1.50 +/- 0.78 versus 2.35 +/- 1.63). It is concluded that the tissue perfusion in the lower legs of patients with NIDDM is significantly decreased and related to the duration of the disease and condition of blood sugar control. This may contribute to the high incidence of foot gangrene and limb loss in patients with NIDDM.(ABSTRACT TRUNCATED AT 250 WORDS)