The invention relates to a cleaning agent, particularly for cleaning sewers, for fat and/or protein-containing sewage from the home or having a municipal or industrial origin, with a content of urea, a urea derivative, a urea salt and/or a urea derivative salt, the cleaning agent containing approximately 50 to 90 wt. % urea, urea derivative, urea salt and/or urea derivative salt, based on dry substance, and an alkaline-acting agent, protease and fat-degrading microorganisms.
