Abstract: The invention relates to a headbox for a machine for producing a fibrous web, in particular a paper or cardboard web, from at least one fibrous stock suspension, having a feed apparatus which feeds the at least one fibrous stock suspension, having a distributor-pipe perforated plate which is adjacent downstream and has a multiplicity of channels which are arranged in rows and in columns, having an intermediate channel which lies downstream of the latter, extends over the width of the headbox and has a plurality of means which are spaced apart from one another in the width direction of the headbox for the preferably regulatable/controllable metering of a fluid in fluid part streams into the at least one fibrous stock suspension.