A routine X-ray examination of the sinuses of a patient complaining of regular bouts of dizziness may provide diagnostic information about a so-called sinugenic vertigo. In addition to the pathological X-ray findings in the maxillary sinuses, the patients presented either a positioning nystagmus or a head-shaking nystagmus, with disturbed vestibular spinal reaction as a pathological vestibular condition. Out of 15 patients in whom a sinusitis-induced (sinugenic) dizziness was diagnosed and who appeared regularly for the control checks, 14 patients said that they were relieved of the dizziness as a result of sinus therapy, often immediately afterwards. Interrelationships possibly exist between pathological trigeminus reflexes via the sphenopalatine ganglion brought about by maxillary sinusitis and a reflectory labyrinthine irritation, triggering the vertigo.