The present invention relates to the use of an absorption liquid for purifying a gas by removal of gaseous, acidic impurities. The gas to be purified can be any gas, such as synthesis gas or natural gas, which contains gaseous, acidic impurities such as CO2, H2S, SO2, CS2, HCN, COS or mercaptans. The absorption liquid comprises:A) from 0.01 to 4% by weight of at least one compound of the formulaB) from 0.001 to 8.0% by weight of water, andC) at least one polyalkylene glycol alkyl ether of the formulato 100% by weight,whereR1 is C1-C4-alkyl,R2 is ethylene or 2-methylethylene,R3 is hydrogen or C1-C4-alkyl,R4 is hydrogen or C1-C4-alkyl,R5 is C1-C4-alkylene andX is an integer from 1 to 10. The amine may be N-methyldiethanolamine and the ether may be polyethylene glycol dimethyl ether.