A piercing part for a medical infusion system includes a housing with a piercing mandrel, a fluid channel and a ventilation channel with a first channel portion extending at least substantially parallel to the fluid channel and with a second channel portion diverted towards an outside of the housing and to which an air filter element and a fluid shut-off member are assigned. A drip chamber can include a piercing part. The piercing part can be produced by an injection molding tool. The second channel portion in the housing is oriented parallel to the first channel portion and open towards an inside of the housing. An open region of the channel portion is closed by a separately produced closure part. The piercing part can be used with a medical infusion system.