A hermetically-sealing opening dispensing lid made of injected plastic material for foodstuff packages of solid, dry, powdered or grain products is made up of a movable body hinged to a frame by means of a hinge, the frame is secured to the package by perimeter ridges and ultrasonic welding or by an edge which goes through the wall of the package and joins an inner counter frame, the movable body is made up of two lateral walls with retaining elements which act on tabs placed at the top of the frame, a front wall with a hinged gripping flange, an upper bridge and a lower bridge, the lid is provided with racks spaced from the lateral walls which cooperate with a second pair of tabs, and the bridge may contain a set of parallel ribs preventing the products from going through the movement zones.