PURPOSE: To prepare the title agent which masks and gradually discolors the yellowish brown color of the human waste, by adding a blue oxazine basic dye to a composition composed of a deodorizer, a detergent, an insecticide, a germicide, a perfume, etc.

CONSTITUTION: The title agent is prepared by adding a blue oxazine basic dye as an agent for masking the yellowish brown color of the human waste to a conventional waste-treating agent. Monoxazine, which is an oxazine blue dye, can be prepared by the condensation and oxidation of a p-nitrosoaniline derivative with phenol, naphthol, or an aromatic amine, and dioxazine is prepared by condensing chloranil with an aromatic amine. The oxazine dye is pref. 3,7-bis-(diethylamino)- 1-ethoxyphenazoxonium chloride, etc.