Abnormalities in cutaneous blood flow (CBF) in otherwise healthy subjects with Type 1 diabetes mellitus (DM) have been demonstrated in response to local insults to the skin. To investigate whether defects also occurred in response to a regular daily activity, CBF was measured with laser Doppler flowmetry (LDF), before and 20 min after starting a mixed meal in 13 male Type 1 DM subjects with no clinical evidence of neuropathy, nephropathy or macroangiopathy and compared to 7 non-diabetic controls. Diabetic subjects and controls were of similar age and body mass index (mean Β± SD, 33.7 Β± 7.4 vs 37.1 Β± 9.2 years and 25.2 Β± 2.9 vs 24.5 Β± 2.9 kg m -2 , respectively). In subjects with DM, HbA 1c was 8.3 Β± 0.6 % (normal range 4-5.5 %) and duration of diabetes was 18 (8-38) years, median (range). Following a mixed meal the CBF fell in the controls by 36 % (24 to 56), median (range), compared to 3 % (-5 to 18) in Type 1 DM subjects, P Ο½ 0.0005. These results show there is a normal physiological fall in CBF following food ingestion which is attenuated in Type 1 DM. These abnormalities of vasoconstriction in the peripheral microcirculation are present after 8 years of diabetes and precede the development of clinically apparent neuropathy or vascular disease.