The present invention is drawn to an agent and process for altering the color of keratin fibers wherein the agent comprises: (A) a color base composition containing from about 5% to less than about 50% by weight of a fatty substance a rheology modifying polymer an alkalizing agent and a short alkyl chain hydroxy compound chosen from monoalcohols and polyols an oxidative dye precursor and an oxidizing composition comprising, an oxidizing agent and wherein the pH of the agent for altering the color of keratin fibers ranges from about 1 to about 7.
