Many ethnographic artefacts in collections incorporate monocotyledon leaves. Monocotyledon leaves have parallel venation in which fibres run parallel to the long axis of the leaf. These leaves typically have high tensile strength parallel to their long axis. These plant materials have been the subject of relatively little investigation by conservation scientists. This paper discusses a method developed for applying tensile testing to monocotyledon leaves which draws on practical methods and theoretical concepts used in biomechanical research. The results of this method applied to the material raffia are discussed. This material, derived from the leaflets of Raphia palm, frequently becomes brittle and fragile on ageing.