A fluid dispenser including, a fluid reservoir with a neck externally threaded and that internally defines an opening that communicates with the inside of the reservoir, the neck forming at least one helical thread; and a dispenser head that is mounted on the neck by a fastener member in engagement both with the threaded neck and with the dispenser member. The fastener member includes a ring, the ring forming: a reception mechanism for receiving the dispenser member; an annular ledge; and a skirt that is in engagement with the threaded neck. The ring includes a rupture mechanism between the ledge and the skirt so as to separate the ledge from the skirt by turning the ring on the threaded neck, in such a manner as to remove the dispenser member from the reservoir.