OBJECTIVE--To assess treatment with fludrocortisone in vasodepressor carotid sinus syndrome. PATIENTS AND METHODS--Eleven patients, mean (SD) age 83 (5) years, with daily dizzy episodes and a median of five (range two to 20) syncopal episodes over a median of one year were studied. All had vasodepressor carotid sinus syndrome (> 50 mm Hg fall in systolic blood pressure during carotid sinus massage independent of bradycardia). Carotid sinus massage was carried out while the patient was supine and upright (tilt table) before and after 600 micrograms intravenous atropine. Phasic heart rate and blood pressure recordings were monitored throughout. The study was repeated after 100 micrograms of fludrocortisone daily by mouth for two weeks. Patients continued to take fludrocortisone for a six month follow up period. RESULTS--Baseline systolic blood pressure was (mean (SD)) 169 (31) mm Hg and the RR interval was 770 (150) ms. After carotid sinus massage, systolic blood pressure fell to 113 (27) mm Hg (p < 0.01) and RR was 1060 (210) ms (NS). The vasodepressor response was 56 (12) mm Hg. Baseline systolic blood pressure after two weeks of fludrocortisone treatment was 171 (37) mm Hg (NS); but the fall in systolic blood pressure during carotid sinus massage was significantly reduced (32 (14) mm Hg; p < 0.01). At six months follow up, two patients complained of intermittent dizziness and no patients had syncope. CONCLUSION--Fludrocortisone effectively reduces the vasodepressor response and relieves the symptoms of vasodepressor carotid sinus syndrome.