Abstract: A dispenser for releasing a volatile active substance from a carrier material that contains the active substance in liquid form in a receptacle is impermeable to liquid, said dispenser comprising a base circular part with supporting members for said carrier and sidewall sections on which an upper circular part with cylindrical sidewall, pierced by side apertures for the emission of the volatile active substance, is pivoted. The upper circular part has on the inner disc-shaped surface thereof one or more decentrally positioned flexible blades which are able to pierce the sheath of the receptacle containing the active substance or to impale it on a spike by rotating the circular parts relative to each other in order to activate the carrier material by impregnating it with volatile active substance.