a plastic spout which is adapted to be sealed between two foil walls of a pouch . the spout has a spout body , which forms a passage for delivering a medium from the pouch and / or feeding a medium to the pouch . in a bottom part thereof , the spout , on opposite sides , forms a sealing zone for a sealed connection to an adjoining foil wall . the sealing zones of the spout body are formed by sealing walls which project downward from the spout body . the sealing walls can preferably move flexibly transversely with respect to their plane and , on their inner side , are unsupported or are supported by one or more flexible supporting parts of the spout body .