Abstract: Syringe of the type comprising a hollow cylindrical body 11 having a bottom closing part 14 bearing a connecting joint for a needle and in which there is arranged in a sliding manner a piston 12 driven by a stem 17 and fitted with a sleeve 13 sliding on the outside of said body 11. Said sleeve 13 is provided with first engagement means 26 designed to engage with said body 11 and prevent movement in one direction and second engagement means 25 designed to engage with the drive stem 17 of said piston 12 to similarly prevent movement in the other direction.