The invention relates to pharmaceutical compositions designed to leave aprotectivefilm on the skin, comprising chitosan and agents conferring curative, calmingand hydratingproperties on irritated skin. The gel is characterised in that it includesbetween 2 and 8 %chitosan and pre-defined proportions of other components such as between 0.1and 90 %Portulaca and between 0.1 and 45 % Panthenol, which confer improvedtherapeuticcharacteristics on the product, and other components which provide the gelwith particularcharacteristics and render same suitably stable over a prolonged period oftime. Said gel isapplied externally and is suitable for use on irritated skin, superficialburns, dermabrasions,post-dermabrasion, post-laser treatment and on eroded skin in general.