A method for preparing a substantially dry cross-linked gelatin powder is described. The method comprises providing a solution of a non-cross-linked gelatin and then cross-linking the non-cross-linked gelatin while in solution in the presence of a rehydration aid. The cross-linked gelatin is then washed to remove at least 50% w/w of the rehydration aid, dried and the dry solid ground to produce a cross-linked gelatin powder typically having a moisture content below 20% w/w. A composition comprising a cross-linked gelatin powder that was cross-linked in the presence of a re-hydration aid is also described. The powder has an aqueous re-hydration rate of at least 3.0 g/g.
