Within the last 10 years there has been increasing recognition of the frequency of spontaneous occlusions of the carotid arteries as a cause for neurologic deficit, and several reports of successful therapy instituted early in the disease have appeared. Since many patients with symptoms due to carotid occlusion will be seen initially by the general practitioner or internist, increased awareness and knowledge of the condition seem warranted. The clinical and laboratory features of 50 patients with proved carotid occlusions are presented, the varying clinical pictures produced by such occlusions are described, and the potential means of therapy are discussed.