1. Macro- and microvascular diseases are the main chronic complications of diabetes mellitus (DM). 2. It has been shown that DM patients have more severe nailfold microcirculatory disturbances than patients with liver cirrhosis or systemic lupus erythematosus (SLE). 3. It has been shown that the glomerular basement membrane of diabetic rats is significantly thickened compared with that of normal rats (295.5 +/- 45.1 vs 184.8 +/- 33.2 nm). 4. Gastric mucosal blood flow (GMBF) in 41 patients with non-insulin-dependent diabetes mellitus (NIDDM) was determined with a laser Doppler flowmeter. The results showed that average GMBF values at 14 sites in the gastric mucosa were significantly lower in NIDDM patients than in control subjects. 5. The percentage of painless acute myocardial infarction (AMI) among 50 patients with DM was 22.0% and the mortality of AMI was 22.0% (11 cases). Both these values were higher than the corresponding values in patients without DM (9.9 and 11.4%, respectively; P < 0.05). 6. Cerebrovascular disease is more prevalent in diabetic patients than in non-diabetics and the mortality of stroke in DM patients is two-fold higher than that of non-diabetic patients. 7. Diabetes can result in widespread macrovascular atherosclerosis and microcirculatory disorders of multiple organs.