Teased fibre preparations are important in the investigation of periph
eral nerve disorders, but can be a rather tedious procedure. A techniq
ue is described in which pretreatment of the nerve sample with collage
nase before osmication substantially simplifies the actual teasing pro
cedure. The technique also does not alter the morphology or interfere
with any further investigations required on teased fibres-for example,
fluorescent antibody studies.