Angiogenic therapy is one of the new treatments of ischaemic heart disease. Oestrogen has angiogenic properties under hypoxic condition, and if oestrogen also induces angiogenesis under normoxic condition, it could be used in combination with other angiogenic therapies in the treatment of ischaemic heart disease. In this study, we evaluated the angiogenic effect of high-dose oestrogen treatment in normoxic rat heart tissue. Fifty-two ovariectomized rats were randomized in oestrogen-treated and control groups. 17 β -Oestradiol (1 mg /week) and normal saline (1 mg/week) were administered intramuscularly in the treatment and control groups for 2 months. After that, coronary capillary density and coronary vessel permeability were measured. The serum vascular endothelial growth factor (VEGF) level was also measured before and after the treatment. The results indicate that coronary capillary density (number of capillary per square millimetre) and coronary vessel permeability (fluorescence intensity) were significantly higher in the oestrogen-treated group than in the control group (628 ± 26 per mm 2 versus 540 ± 26 per mm 2