The cellulase activity of grey forest soil polluted with the fungicide copper sulphate was studied after the application of various ameliorants (calcium carbonate, sodium nitrate, microcrystalline cellulose, activated carbon and zeolite). The main criterion was the soil’s capacity to decompose cellulose, determined by the application (weight loss) method. The application of calcium carbonate, sodium nitrate and zeolite was found to stimulate soil cellulase activity, while the application of microcrystalline cellulose and activated carbon inhibited it.