The present invention relates to a biological film-forming agent which is forfacilitating wound healing and coating and protecting biological organs, andfor coating andprotecting damaged cells, wound surfaces, organs and damaged sites of organs,and woundsurfaces reaching soft tissues such as muscle and facia, periosteum or bonecortex. Providedis a biological film-forming agent for suppressing exudation of intracellularfluid fromdamaged cells, suppressing expansion of inflammation reactions and secondaryinflammationreactions resulting from production of fibrin and eliminating adverse effectscaused byformation of stabilised fibrin on healing. Various problems can be solved byusing the agentcontaining aluminium chloride, cyclodextrin and water as base components.