Serum bromide levels were measured in 115 anesthetists by use of x-ray fluorescence spectrometry. Bromide levels peaked at 184 ± 21 µM in anesthetists regularly exposed to halothane (n = 20), at 58 ± 4 µM in anesthetists sporadically exposed to halothane (n = 71), and at 46 ± 3 µM in nonexposed anesthetists (n = 24). Kinetic studies were carried out in five other anesthetists after ten days of exposure to halothane. Average daily halothane concentration was 19.2 ± 3.2 ppm; duration of exposure was 3.8 ± 0.2 hours/day. Mean serum bromide level increased from 40 ± 4 µM before exposure to 220 ± 36 µM on the last day of exposure. Serum bromide half-life was 14 ± 1.7 days. The study demonstrates that anesthetists debrominate halothane in a doserelated fashion. Serum bromide levels achieved, however, were far below those reported to result in clinical bromism.