The present invention relates to a collagenous material and to a process for the manufacture thereof. The process is for the manufacture of a collagenous material from a plurality of collagen particles, wherein said collagen particles are derived from a natural tissue material and are substantially free of non-fibrous tissue proteins, cellular elements and lipids or lipid residues, and wherein said collagen particles comprise fragments of collagen fibres displaying original collagen fibre architecture and molecular ultrastracture of said natural tissue material, said process comprising steps of: treating the collagen particles with an aqueous acid solution to swell the collagen particles and collectively dehydrating the swollen collagen particles. The collagenous material may be used, for example, in wound care.