Fibres suitable for use in the production of wound dressings comprise carboxymethyl cellulose and alginate in a total amount of at least 90% by weight of the fibre, the carboxymethyl cellulose and alginate are homogeneously distributed throughout the fibre and are present in amounts such that: (a) the amount of carboxymethyl cellulose present in the fibre is at least 50% by weight of the total weight of the carboxymethyl cellulose and alginate (b) the alginate has a Guluronate-content of 50-90% by weight, and (c) the value of z given by the expression (1): z=(2x/40)/(2x/40)+(y/23) where x and y are the percentages by weight of calcium and sodium respectively in the fibres is at least 80. The fibres may be produced by spinning a solution comprising dissolved CMC and alginate in appropriate proportions into a coagulation bath containing calcium ions.