Activation of peroxisome proliferator activated receptor alpha (PPAR.alpha.) by administration of therapeutic amounts of a PPAR.alpha. agonist, WY-14643, inhibits the proliferation of vascular smooth muscle cells, hepatoma cells and human renal proximal tubule cells. WY-14643 may be applicable as a medicament for the treatment of proliferative vascular disease (atherosclerosis, hypertension), revascularization-induced injury (restenosis) and chronic renal failure.