The present invention relates to a gel-forming agent comprising a sulfa agent and a chitosan agent and having a powdered dosage form. In addition, the present invention provides a kit comprising the gel-forming agent of the present invention and a method comprising a step for applying the gel-forming agent of the present invention. According to the present invention, a gel-forming agent is provided that demonstrates a therapeutic effect that is more remarkable than that of conventional sulfa agents and chitosan agents alone, and more particularly, a gel-forming agent for protecting an exudative affected area and a gel-forming agent for treating a wound. Namely, by the applying the combination of a sulfa agent and a chitosan agent in the form of a powder, the pH of the affected area is maintained in a range that demonstrates a therapeutic effect, and antibacterial action of the sulfa agent is demonstrated. In addition, the moist environment at the affected area is suitably maintained for suitable granulation. In addition, as a result of being a powder, the use of a suitable dissipating container enables the gel-forming agent to be dispersed by a person performing treatment without making direct contact with the affected area.