Fibrillation of certain cellulosic fibres has been widely studied, and fibrillation can be utilised to improve fabric performance, for example strength, absorbency, surface area together with handle and opacity. However, it believed that keratinous fibres such as wool have not been treated in this way. The invention seeks to provide a fibrillated keratinous fibre fabric and a method of fibrillating natural fibres. A textile fabric of keratinous fibre is disclosed characterised by the presence of fibrils, micro-fibrils and proto-fibrils. The fibrils may be further characterised as having diameters in the range 3 mum to 5 mum and by having lengths in the range 25 mum to 60 mum. Preferably, the fabric is a woven, knitted, non-woven or composite fabric. A method of treating natural fibres is also disclosed which comprises:- a pre-treatment to remove surface lipid materials or scales, e.g. using an oxidising agent; a treatment to remove or partially remove intercellular cement, e.g. using an enzyme; and the application of mechanical agitation under aqueous conditions, e.g. hydroentanglement, to complete fibrillation.