It is accepted practice to prescribe β-blockers in order to retard aortic dilatation and prevent aortic dissection and rupture in patients with Marfan syndrome. A critical review of the published pharmacological studies shows this practice to be based on limited evidence. The data from small clinical and experimental studies with surrogate end points suggest greater potential benefit from alternative drug regimens, and a recent experimental study showed that losartan may interrupt the mechanism of disease as well as deal with its functional consequences. It is now essential to perform large, collaborative, randomised controlled trials with clinical end points of new treatments in Marfan syndrome.