An injection appliance including a housing, a product container received by the housing and containing a product, a piston received in the housing in such a way that it can be displaced in a forward direction to dispense the product, a piston rod which acts on the piston in the forward direction, and a spring which acts on the piston rod in the forward direction, wherein, in one embodiment, the spring includes at least two adjacent spring sections each having a different buckling resistance in relation to the same length when the piston rod is a forward position and, in another embodiment, the appliance includes a spring guiding structure that is entrained or in use during a forward movement of the piston rod and secures the spring against buckling, wherein, when the piston rod is in the forward position, the guiding structure extends past an end of the rod.