The present invention relates to an apparatus for a sterile dispensing of liquids at low pressure. The apparatus comprises a liquid container (2) having a substantially rigid wall and an upper filling aperture, the liquid container further comprising a liquid space (15) having a predetermined volume and a gas space (16) having a predetermined volume; a deformable gas container (21) arranged externally to the liquid container (2); a container closure unit (1 ) sealingly coupled to said upper filling aperture of the liquid container (2) and said external gas container (21), said a container closure unit comprising a first means for dispensing the liquid from the liquid container (2), and a second means for establishing a fluid communication between the gas space (16) of the liquid container (2) and the external gas container (21), said second means comprising a two-position valve assembly (7) allowing the gas, in a first position, to flow from the gas container (21) into the liquid container (2), and in a second position, to flow from the liquid container (2) into the gas container (21); and an operating unit (25) removably coupled to said container closure unit (1), said operating unit comprising operating members for operating said first and second means of the container closure unit (1) from outside.