Microangiopathic disorders, characterized by capillary vasodilation and increases in capillary blood flow and permeability, are common in diabetes and can occur before the development of microangiopathic complications. In a study of 163 diabetic patients, capillary permeability, measured by albumin retention (AR), was increased in 39% of patients. AR was increased more frequently in women than in men, and in patients without microangiopathic complications than in patients with complications. Increased AR was significantly associated with insulin-dependent diabetes in male patients. Lymphatic function was abnormal in 72% of patients; this abnormality was often present before AR increased. The pathophysiology of microangiopathy is complex and involves metabolic, haemodynamic, neurological and hormonal factors. Improved control of glycaemia and blood pressure can reduce capillary permeability. In addition, studies with a flavonoid fraction and n-3 polyunsaturated fatty acids suggest that these agents may also be beneficial.