The present invention relates to a composition for dyeing keratin fibers, comprising a) one or more fatty substances, which are preferably liquid and non-silicone, b) one or more cellulose polymers and/or one or more carboxylic anionic, c) (2,5-diaminophenyl)ethanol, d) optionally, one or more couplers, e) optionally, one or more basifying agents, and f) one or more chemical oxidizing agents such as hydrogen peroxide, and the content of fatty substances in the composition representing in total at least 10%, in particular at least 15%, more particularly at least 20% and preferably at least 25% by weight relative to the total weight of the composition resulting from the mixing of (A′)+(B′)+(C′). The present invention also relates to a process using this composition and to a multi-compartment device suitable for the use of said process.