Abstract: A scrubber for desulfurization of gases, in particular flue gases of a boiler furnace includes two scrubbing zones each having a plurality of spaced arrays of nozzles for washing the gas with a respective washing liquid containing sulfur compound binding additives. At the bottom portion of the scrubber, the liquid discharged from the nozzles and containing sulfur compounds forms a sump to which limestone is added. From the sump two circulation systems extend. Each circulation system includes a pump which draws off a respective washing liquid from the sump and conveys the latter to the associated one of the scrubbing zones whereby whitewash or lime milk is introduced into one of the circulation systems.