Angiograms in patients with motor seizures of recent onset may give evidence for swelling in the frontal operculum. The opercular swelling may mimic a mass lesion on lateral arterial phase angiograms, but frontal views show no shifts. There may be narrowing of one or more middle cerebral branches in some cases. Although brain swelling commonly accompanies many types of focal neuropathology associated with seizures,19 the cases presented illustrate that it can also occur in patients without definite prior neurologic disease, especially when the seizures are metabolic in origin and arise in association with an increase in tissue water. Seizures in chronic alcoholics often fall into this category, as do some seizure states in diabetics. It is suggested that the angiographically demonstrated swelling is probably largely due to gliosis resulting from previous damage to the blood-brain barrier, perhaps aggravated by the seizures themselves. The cerebral swelling may be more apparent angiographically in states of increased tissue hydration, because of amplification by the tendency for a disproportionately large intake of water by glial cells.