A foot valve for drip chambers of medical infusion or transfusion apparatuses having an annular valve seat with which a float obturator axially displaceable between a position for closing and a position for opening the valve seat cooperates. A containment cage bush has an elastically deformable lateral wall within which the float obturator floats in a guided fashion, and the lateral wall of the containment bush and the float have respective mutually facing surfaces configured such that a radial deformation of the containment bush applies an axial thrust to the float obturator in the direction of moving it apart from the annular valve seat.
