Abstract: A method and device are disclosed for delivering items into the body of a subject. The device is elongated, and includes a flexible diaphragm having a proximal face and a distal face. The diaphragm is inverted into the device to form a receptacle that holds an item to be delivered. Fluid pressure is applied against the proximal face of the flexible diaphragm to deliver the item from the receptacle and out of the delivery device into the body. In one embodiment, the device is a one-piece device having compressible walls. The diaphragm, which may be a portion of the chamber wall, invaginates within the chamber to form the receptacle. Compression of the flexible walls of the device increases pressure on a proximal face of the diaphragm to evaginate the diaphragm out of the chamber and deliver an item contained in the chamber.