For the simplified construction of a dispenser (10) for substances, comprising an outer casing (13) with a deformable outer wall (12), which encloses a deformable container arrangement (11), and also comprising at least one equalizing valve (23) for equalizing air, wherein an air-filled interspace (14) is provided between the outer wall (12) and the container arrangement, and substances are discharged once the outer casing (13) has been subjected to pressure, it is proposed that the container arrangement should have at least two containers (11 a, b) for the separate storage of liquid or pasty substances. For the long-term storage of said substances, in particular the exit region of the container arrangement (11) has a diffusion seal, in particular made of metal, which, just prior to the dispenser (10) being used, is pierced, and opened, from the dispensing head (15), in particular using spikes.