A composition is described for a topical application, in the form of a rinse-off mousse, including no or only a small quantity of foaming surfactants. The composition can include a medium that is cosmetically or pharmaceutically compatible with a topical application, and benzoyl peroxide. The composition can also include at least one intermediate composition, at least one gas-generating agent, at least one agent activating the at least one gas-generating agent, and benzoyl peroxide. A kit or a single container with a plurality of compartments including this composition is also described.