Dispensing assembly having a syringe (100) comprising a body (102) provided with a ball (104) supporting a needle (A) provided with a tip (P), and a removable guard (10) for a syringe needle, said guard (10) having an elastic cap (20) which defines an inner cavity (26) delimited by a lateral wall (28) and by a distal end wall (30), said end wall (30) being solid and receiving said tip (P) of said needle (A) of a syringe (100) in a leaktight manner in the protection position, said lateral wall (28) having an annular bead (70) provided with at least one slit (72) extending in the longitudinal direction on said annular bead (70), said annular bead (70) cooperating in a leaktight manner, in the protection position, with said ball (104) of the syringe, said cavity (26) of said cap (20) being dimensioned in such a way that, when said guard (10) is removed from said syringe (100), said cavity (26) is connected to the atmosphere via said at least one slit (72) before said tip (P) of the needle (A) is connected to said cavity (26).
