Synthetic vascular grafts have a thrombogenic surface which probably is an important factor in graft failure. Systemic pharmacologic intervention has been used but is associated with side effects. In this communication we describe the results of a new therapeutic principle of applying forskolin, a powerful cyclic adenosine monophosphate stimulator (cAMP), to the inner surface of a synthetic graft material, polytetrafluoroethylene. Evaluation was done with Indium-111-oxine labelled platelets and histopathology. It was found that forskolin significantly lowers the platelet deposition onto the treated graft surface compared to controls.