Abstract: In one aspect, the present invention is directed to a tube-dispenser comprising: a piston, deployed inside the tube of the dispenser, for pushing the substance stored inside the dispenser towards the outlet of the dispenser; and a no-return mechanism for preventing the piston from falling back. According to one embodiment of the invention, the no-return mechanism is entirely deployed inside the tube. In one embodiment of the invention, the no-return mechanism comprises: a ribbed surface deployed along the interior wall of the tube; and at least one dowel attached to the piston correspondingly to the ribbed surface. In one embodiment of the invention, the ribbed surface comprises cogs. Preferably the cogs are of sawtooth form. The ribbed surface may also be a track along the tube, thereby enabling utilizing more dispensed substance than in the case where the ribbed surface is on the entire wall.