High levels of factor VII are associated with an increased risk of death from cardiovascular disease, especially ischaemic heart disease (IHD). Theoretical considerations and experimental evidence, the latter including the results of clinical trials, suggest that the association may be one of cause and effect. The general epidemiology of factor VII also supports this view. Thus, characteristics such as increasing age, diabetes, obesity, the use of oral contraceptives and the occurrence of the menopause are each associated with raised factor VII levels as well as with an increased risk of IHD. Black ethnic group and vegetarianism, both apparently protective against IHD, are associated with low factor VII levels.