Double filtration plasmapheresis (DFPP) was performed in a patient with Bickerstaff's brainstem encephalitis (BBE) in its early phase. He was a 27-year-old male patient suffering from diplopia, facial palsy and drowsiness following upper respiratory tract infection, and had high titers of immunoglobulin G (IgG) antibodies against ganglioside NeuAc(alpha)2-8NeuAc(alpha)2-3Gal(beta)1-3GalNAc(beta)1-4(NeuAc(al pha)2-8NeuAc(alpha)2-3)Gal(beta)1-4Glc(beta)1-1'Cer (GQ1b) in the serum. DFPP effected immediate improvement of his drowsiness, supporting the diagnosis of BBE. Our observations suggest that DFPP during the early phase of BBE efficiently prevents the progression of consciousness disturbances.