a dispensing pump for liquid or pasty products comprising a housing , a piston arranged to move telescopically within the housing between rest and activated positions and a plastics spring arranged to return the piston from its activated to its rest position . the plastics spring has a folded , concertina configuration to provide the required return force for the piston . the spring also has end plates , which can be adapted increased functionality . the whole pump may be moulded from a plastics material and has few component parts .