The invention relates to the use of polyamine compounds having an aliphatic linker comprising from 2 to 5 carbon atoms in the presence of chemical oxidizing agents, for treating keratin fibres, in particular as a replacement for aqueous ammonia and/or monoethanolamine (MEA), to a process for treating keratin fibres using said particular polyamine compounds in the presence of chemical oxidizing agents, and to a multi-compartment device comprising same. The compounds of formula (I) according to the invention combined with the ingredient(s) ii) make it possible to obtain a good level of performance especially in terms of lightening of keratin fibres, while at the same time maintaining integrity of the keratin fibres that is comparable to or even greater than MEA. In addition, no unpleasant odour associated with the compounds of formula (I) in the presence of oxidizing agent is observed.
