The invention relates to a method for operating a wet gas scrubbing unit as well as to a wet gas scrubbing unit in which substances of a first type and substances of a second type are separated from a gas mixture (1) by a wet scrubbing process by means of a physically active scrubbing agent (2) in which the substances of the second type are more readily soluble than the substances of the first type, and a first (12) scrubbing agent (10), which is loaded with substances of the first type and contains hardly any substances of the second type, and a second scrubbing agent (10), which is loaded with substances of the first and second types, are obtained; during regeneration of the scrubbing agents (10), the second loaded scrubbing agent (10) for separating substances of the first type is released into a first column (M) so as to reduce its pressure a first pressure and is then released into a second column (E) so as to reduce its pressure to a lower second pressure; in the first column (M), a first portion (11) of the first loaded scrubbing agent (12, 14) is used for backwashing substances of the second type, and in the second column (E), a second portion (15) of the first loaded scrubbing agent (12, 14) is used for backwashing substances of the second type converted into the gas phase during the pressure reduction; before being used in the second column (E), the second portion (15) of the first loaded scrubbing agent (12) is expanded in a separator (D3) so as to obtain a liquid phase which has a lower concentration of substances of the first type and which is transferred into the second column (E) with the aid of gravity. The method of the invention is characterized in that an apparatus that can be operated independently of the first column (M) and the second column (E) is used as the separator (D3) in which the pressure of the second portion (15) of the first loaded scrubbing agent (12) is reduced to a third pressure which is higher or lower than the first pressure.