Abstract: An inhalation device for powdered medicaments in which the opening of the container in which the medicament is initially contained is achieved simply and reliably in situ in the device, the device being provided with means (24) for locating the container in a position to be opened and with appropriate opening means (20, 21) for the container, said opening means being normally in a non-opening position but movable successively into and out of a container opening position by movement in one direction of a cam surface (7, 8, 30, 31) acting thereon, the cam surface being provided with a step or steps (9, 10) to prevent reverse movement of the cam surface after opening of the container has been achieved. The cam surface (7, 8) is preferably provided on one housing member (1) and the opening means (20, 21) on a second housing member (2) so that attachment of the housing members (1, 2) simultaneously opens the container.