With soap and cleansing foam dispensers, there is a risk that they may be equipped with supply containers of unsuitable liquid or that their intermediate containers may become contaminated. According to the invention, an adapter (8) that is mounted on an intermediate container (6) has a coded cylindrical jacket (10), into which coded parts (4,5) that are positioned on the neck of a suitable supply container (2) can be fitted. To prevent the contamination of the intermediate container (6), the latter has a spring-loaded internal sealing plug (50) which ensures the hygienic sealing of the container even prior to use and when the supply container is changed. To prevent interruptions in the operation, a reliable fill-level indicator (22) is provided. The device thus ensures improved, hygienic dispensing of soap-solution in dispensers (1).