SummaryHorton’s disease (also called temporal, cranial or giant cell arteritis) is a diffuse disease of the vessels, of unknown origin (bacterial allergy ?), affecting old people.It begins with non-specific symptoms (malaise, loss of weight, anorexia, fever) followed by severe head aches accompanied by inflammation of one or more of the temporal arteries.It is often complicated by severe ocular symptoms (amblyopia, amaurosis) and by other less frequent localizations (brain, myocardium, mesenterium, etc.).It is characterized by successive phases of progress and remission lasting, on the average, from 2 to 6 months.Prognosis quoad vitam is relatively good.Pathology evidences lesions of periarteritis with giant cells involving mainly the cranial arteries.Blood sedimentation rate is always much increased. Protidemia is perturbed with increase of theα2and theγglobulins and decrease of the albumins.Results of therapy associating antibiotics with ACTH or the corticosteroids appear to be most encouraging.