The invention comprises a disposable hypodermic syringe with means for passive aspiration. The syringe comprises a barrel (10) of clear synthetic plastics material and a plunger (12) comprising an elastic bung (28) slideable in the barrel (10). Pressure on the plunger elastically deforms the bung (28). If this pressure is released the bung (28) resiles to effect aspiration. This aspiration is passive, requiring no active withdrawal of the plunger by the user. After use the syringe may be disposed of as a whole, with no disassembly, using one hand only. The syringe may be made by adapting cartridges conventionally used for dental local anaesthetic.