A hood with a pull-out steam shield, comprising: - a ventilating unit having a gas intake section; - a collecting section, located upstream from the intake section of the ventilating unit, which is adapted to receive a gas flow therethrough in the direction from the outside environment to said intake section; - a frame designed to contain said ventilating unit and said collecting section; - a steam shield located upstream from said collecting section and moving relative to said frame between a rest state in which it is contained within the footprint of said frame and closes said collecting section and an operating state in which it projects out of the footprint of said frame and exposes said collecting section to the outside environment; - a pair of support members rigidly joined with the steam shield each having a pair of cam followers which slidably engage respective tracks rigidly joined with said frame; - each track comprising at least one first inclined section and a second section connected to the first section; - guide members operable on said support members to allow said support members to move between a rest state in which said steam shield is contained within the footprint of said frame and closes said collecting section and an operating state in which said steam shield projects out of the footprint of said frame and exposes said collecting section to the outside environment characterized in that said guide members comprise a pair of racks and a pair of pinions, each pinion of each pair meshing with a respective rack and being slidably engaged with a respective support member, thereby guiding said pair of support members as they move, each pinion of said pair of pinions being linked to the other by means of a connecting rod, said connecting rod being rigidly engaged with another end of each pinion of said pair of pinions. - a ventilating unit having a gas intake section; - a collecting section, located upstream from the intake section of the ventilating unit, which is adapted to receive a gas flow therethrough in the direction from the outside environment to said intake section; - a frame designed to contain said ventilating unit and said collecting section; - a steam shield located upstream from said collecting section and moving relative to said frame between a rest state in which it is contained within the footprint of said frame and closes said collecting section and an operating state in which it projects out of the footprint of said frame and exposes said collecting section to the outside environment; - a pair of support members rigidly joined with the steam shield each having a pair of cam followers which slidably engage respective tracks rigidly joined with said frame; - each track comprising at least one first inclined section and a second section connected to the first section; - guide members operable on said support members to allow said support members to move between a rest state in which said steam shield is contained within the footprint of said frame and closes said collecting section and an operating state in which said steam shield projects out of the footprint of said frame and exposes said collecting section to the outside environment