Elevated oestradiol (E2) levels may be a risk factor for ischaemic heart disease in men, although the mechanisms for the elevation of oestrogen and for its adverse effects remain unclear. We have studied 100 Caucasian males undergoing elective coronary angiography for ischaemic chest pain and measured serum oestradiol, a profile of haemostatic tests, extent of coronary artery disease and evidence of previous myocardial infarction in order to assess any relationships which could explain the effect of elevated serum oestradiol levels. Levels were significantly higher in men with a history of myocardial infarction compared to those without (p less than 0.01), but were unrelated to the extent of coronary disease or to the haemostatic tests. These results suggest that the association of oestradiol with coronary events relates to myocardial infarction, not to atherogenesis, and is not due to any currently measurable alterations of haemostasis. Current beta-adrenoceptor blocker treatment was associated with lower oestradiol and thromboxane B2 concentrations (both, p = 0.06). These incidental findings suggest that further studies of the effects of beta-blockade on oestradiol and thromboxane metabolism are indicated.