PURPOSE: To obtain a composition for the oral cavity useful for suppressing a formation of bacterial plaques and preventing gingivitis by allowing to contain a cationic germicidal agent and polyvinyl pyrrolidone and no detergents except the cationic germicidal agent.

CONSTITUTION: This composition for the oral cavity is allowed to contain 0.0001-50wt.% cationic germicidal agent (e.g. benzethonium chloride) and 0.001-20wt.% polyvinyl pyrrolidone having 10000-360000 average molecular weight as a stabilizer thereof. This composition is prepared to formulate a mouth refrigerant such as a tooth paste, a liquefied tooth wash, a tooth wash, a moistened tooth cleaner, a mouth wash, a mouth spray, etc., a teeth coating agent, a dental prosthesis coating agent, a dental prosthesis cleaning agent, etc., by usual methods. Here, a surfactant except cationic germicides is not included. This composition makes the most of the germicidal activity of the cationic germicide and is excellent in stability with the passage of time.