Thirty-six subjects with confirmed, unilateral benign paroxysmal positioning vertigo of at least 2 months' duration were randomly assigned to one of two treatment groups. After complete informational counseling and explanation of the posttreatment instructions, subjects were randomly assigned to receive either Epley's canalith repositioning procedure or a placebo maneuver. All subjects completed a daily diary for 1 month to document any dizzy spells and their adherence to the posttreatment instructions. Follow-up Dix-Hallpike testing was performed after 1 month by an audiologist who was blinded to the patient's treatment group status. Analysis of Dix-Hallpike results confirmed that those who received the canalith repositioning procedure had significantly more negative responses (88.9%) than did those in the placebo group (26.7%).