To provide an oral cavity cleansing agent which is safe even in case of being swallowed accidentally, easily usable for children in particular without a sense of incompatibility owing to its slight bitterness, and enabling oral cavity inflammation to be eased.

The oral cavity cleansing preparation comprises an aqueous solution containing persimmon juice extract, grape fruit seed extract, selenium and/or vitamin E, and a refreshener and/or sweetener, wherein the content of the selenium and that of the vitamin E are preferably 0.01-0.1 wt.% and 0.1-1.0 wt.%, respectively.