The effect of pirozadil, a new hypolipidemic agent, on cerebral blood flow was tested in anesthetized dogs and compared to that of two other hypolipidemic/antiatherogenic agents, nicotinic acid and pyridinol carbamate. Nicardipine and papaverine, vasodilator drugs, were used as controls. Measurement of cerebral blood flow was performed by attaching an electromagnetic blood flow transducer to the vertebral artery of the anesthetized dog. Pirozadil's effect on increasing cerebral blood flow was almost equal to that of papaverine, less than that of nicardipine and much greater than that of the other hypolipidemic/antiatherogenic drugs, nicotinic acid and pyridinol carbamate. Pirozadil was also shown to significantly diminish vascular cerebral resistance to a much greater degree than nicotinic acid and pyridinol carbamate.