A device and a method for dispensing at least one substance to a patient is presented where the device has a movable first container containing a first substance having a first piston with a first piston rod, a movable second container containing a second substance having a second piston with a second piston rod, an injection device, and a conduit device for guiding the contents of the second container to the first container and the contents of the first container to the injection device, wherein the first and the second piston are each movable via at least one pre-tensioned spring element. A free end of the first piston rod and a free end of the second piston rod are releasably held by a common holding component, and the common holding component is designed in such a way that a movement of the common holding component results in a successive release of the first piston rod and the second piston rod.