Patients with Guillain-Barré syndrome (GBS) and Fisher's syndrome (FS) benefit from plasmapheresis. Specific treatments, however, have yet to be established for Bickerstaff's brain stem encephalitis (BBE). We showed earlier that sera from BBE patients, as well as from patients with FS and GBS with ophthalmoplegia, have autoantibody to GQ1b ganglioside in the acute phase of the disease. We report 2 BBE patients who had high IgG anti-GQ1b antibody titers and were treated successfully with plasmapheresis.