Cocaine has substantial effects on cerebral hemodynamics which may partly underlie both its euphorigenic and toxic effects. Dynamic susceptibility contrast magnetic resonance imaging (DSC–MRI) was used to determine whether a dose-effect relationship could be detected between cocaine administration and cerebral blood volume reduction in human brain. Twenty-three healthy and neurologically normal adult males with a history of recreational cocaine use (3–40 lifetime exposures) participated. Subjects underwent DSC-MRI measurements of relative cerebral blood volume (rCBV) at baseline and 10min after IV double-blind placebo or cocaine (0.2 or 0.4 mg/kg) administration. Placebo administration resulted in superimposable rCBV curves with post-placebo CBV averaging 104 ± 4% (mean ± SE) of baseline, indicating no CBV change. Both cocaine doses induced CBV decreases which were statistically equivalent and post-cocaine CBV averaged 77 ± 4% of baseline (P < 0.002), when measured 10 min following drug administration. These data suggest that DSC-MRI can detect cocaine-induced CBV reductions indicative of vasoconstriction, and that it may be useful for evaluating treatments designed to reduce the cerebrovascular effects of cocaine.