Multi-dose syringe and method of multiple dosing a liquid or semiliquid product

A multi-dose syringe comprising:

• a hollow cylindrical body, containing a product to be administered in a dosed manner and from which a nozzle extends provided with a product outlet opening, and a plunger, sliding within the hollow cylindrical body;
• a helical indentation is formed on an outer surface of the plunger, which comprises a plurality of teeth, each having a first and a second longitudinal surface and a first and a second transverse surface extending, parallel to each other, orthogonally from a respective longitudinal surface and in that it further comprises a flanged dose-setting sleeve, irremovably mounted on one end of the hollow cylindrical body for the entry of the plunger, and a dose-setting ring mounted on the flanged dose-setting sleeve and rotatable with respect thereto and with respect to the plunger,
• wherein, on facing surfaces of the flanged sleeve and of the ring a series of seats and at least one tooth configured to be housed with interference in a respective seat are obtained, respectively, and wherein the plunger is rotatable with respect to the hollow cylindrical body until the first longitudinal surface of a tooth abuts against an abutment surface of the ring, projecting towards the inside of the hollow cylindrical body, so as to set a predetermined dose of the product to be administered.