The present invention relates to a haemostatic patch comprising a porous layer based on oxidized cellulose and a neutralized film based on chitosan, said film comprising a free face and a face fixed on one of the faces of the porous layer, and to the method of preparing said patch comprising the following steps: - a°) preparing a porous layer based on oxidized cellulose, - b°) preparing a film based on chitosan starting from an acidic aqueous solution of chitosan, - c°) fixing the film obtained in b°) on one face of the porous layer, - d°) neutralizing the film obtained in b°), - where step c°) can be carried out before or after step d°), characterized in that: the neutralizing step d°) comprises treatment of said film with a neutralizing composition comprising at least ethanol and ammonium hydroxide (NH
