This paper presents a retrospective study of patients with vestibular hyperreactivity as evaluated by the total duration of nystagmus in the Hallpike differential caloric test. In our material on otoneurological patients, the condition was not more common than in normal populations. On the other hand, there were two groups of patients, viz. patients with supratentorial intracranial tumours and patients with disseminated sclerosis, in whom the incidence of vestibular hyperreactivity was significantly higher. No definite conclusions can be drawn regarding the pathogenesis of this hyperreactivity, but this condition may be used in the diagnosis of disseminated sclerosis and supratentorial intracranial tumours.