Abstract: A single-use syringe which may be constructed for use by drug abusers comprises a barrel (2) and a plunger (13) slidably mounted in the barrel (2) with the plunger stopper (14) sealingly engaging with the inner wall of the barrel (2). Projections (10) extend from the inner wall of the barrel (2) and are located at such a distance from the distal end of the barrel (2) to permit flushing movements of the stopper (14). A breakable joint (20) integrally joins the stopper (14) and the plunger rod (15), and is broken by engagement of the stopper (14) with the projections (10), so that the stopper is retained in the end of the barrel and the syringe is rendered unfit for further use. In one embodiment, the joint is resilient such that the joint moves readily past the projections during full advance of the plunger to inject a drug, but engages the projections thereby breaking the joint, during subsequent withdrawal of the plunger.