Abstract: There is provided a combination product comprising: (A) BH4, a functional derivative or biosynthetic precursor thereof, or a pharmaceutically-acceptable derivative of BH4 or its derivative or precursor; and (B) an inhibitor of the biosynthesis and/or vasopressor function of AII, or a pharmaceutically-acceptable derivative thereof, wherein each of components (A) and (B) is formulated in admixture with a pharmaceutically-acceptable adjuvant, diluent or carrier, as well as the use of such a combination product in the treatment of hypertension and/or conditions characterised by vascular dysfunction and/or lesions.