An early 60s-year-old man suffered reversible dysfunction of the blood-brain barrier (BBB) induced by repeated injection of contrast medium during coil embolization of intracranial unruptured aneurysm. He presented with convulsion during coil embolization, and neurological symptoms of aphasia and right hemiparesis continued for 5 days, and then improved completely. All transient radiological abnormalities were limited to the territory of the left internal carotid artery, where contrast medium was injected repeatedly. Repeated computed tomography, magnetic resonance imaging, single-photon emission computed tomography, and cerebrospinal fluid test findings indicated that temporary dysfunction of the BBB might have occurred. Dysfunction of the BBB in the anterior circulation induced by contrast medium is rare. Tolerance to toxicity of contrast medium may depend on the individual patient, and repeated injection of contrast medium may cause dysfunction of the BBB, leading to toxic dysfunction directly in the brain.