A description is given of the use of an alkylenediamine of the type R₁HN—X—NHR₂, where X is an alkylene radical having from 2 to 9 carbons, R₁ is a hydrocarbon radical having from 1 to 6 carbons and R₂ is a hydrocarbon radical having from 1 to 6 carbons or is hydrogen (H) for removing sour gases from a sour-gas-containing fluid stream, and of a process for deacidifying a fluid stream of this type and a wash liquid or absorption liquid for use in such a process. According to the invention, in at least one absorption step, the fluid stream is brought into intimate contact with a wash liquid, the wash liquid comprising an aqueous amine solution which comprises at least one tertiary aliphatic alkanolamine having from 2 to 12 carbons and an activator of the above type R₁HN—X—NHR₂. The fluid stream which is substantially freed from sour gases and the sour-gas-loaded wash liquid are then separated from one another.