Raised plasma fibrinogen levels are associated with an increased risk of vascular events. This may be mediated by adverse effects of fibrinogen on plasma viscosity, coagulation, platelet activity, inflammation and atherogenesis. However, there is as yet no drug that specifically lowers plasma fibrinogen levels on a long-term basis. Thus, we do not have intervention trials demonstrating that lowering plasma fibrinogen levels will result in a decreased risk of vascular events. However, such a trial may never happen unless a specific agent is discovered or designed. Several drugs that are used in vascular disease prevention (e.g. lipid lowering agents and antihypertensives) may influence plasma fibrinogen levels. Whether such an additional effect accounts for variations in the benefit resulting from the use of different drugs within the same class remains to be established. The debate continues as to whether fibrinogen is just a marker of vascular risk or whether lowering its circulating levels will result in a significant decrease in clinically relevant endpoints. Whatever the case, the measurement of plasma fibrinogen levels is likely to provide a more comprehensive estimation of risk.