The invention pertains to a one-way valve 1, especially for medical use, comprising at least one valve housing, an inlet 22, an outlet 26, and a valve element consisting of a valve body 20 and a valve seal 16. To it make possible for the one-way valve 1 to function reliably even in the case of liquids containing dietary fiber and for the tubing assembly to be filled rapidly, it is provided according to the invention that the valve body 20 comprises a passageway 21, which opens out into a sealing cavity 23 between the valve body 20 and the valve seal 16, and that the valve seal 16 comprises an opening 39, which can be closed in such a way by the valve body 20 upon relative movement of two housing parts 2, 3 that the valve seal 16 rests with a sealing lip 28 against the valve body 20. As part of an infusion kit above the one-way valve 1, a feed pump is used, which produces a feed pressure for lifting the sealing lip 28 from the valve body 20, so that, after the passageway 21 has been closed, the feed pressure ensures a continuous flow of the infusion solution to the patient.
