Drawer structure (10, 110, 210) for dispensing metered amounts of at least one washing agent in a washing machine, in particular a laundry machine, said structure having: - a hollow shell intended to be fitted on a casing of said washing machine; - a drawer defining at least one chamber (16a, 16b) for receiving a washing agent and mounted so as to move in said shell between an extracted position, in which said at least one chamber (16a, 16b) is able to be accessed from the outside and is ready to receive said washing agent, and a retracted position, in which said at least one chamber (16a, 16b) is closed by said shell and arranged for dispensing said washing agent to the outside of said structure; - at least one passage (17a, 17b) which communicates, on one side, with said at least one chamber (16a, 16b) and, on the other side, with the outside of said structure; - at least one pumping member (18a, 18b) arranged for driving a quantity of said washing agent from said at least one chamber (16a, 16b) through said passage (17a, 17b); and - an actuator or electric motor arranged for operating said at least one pumping member (18a, 18b) and for being connected to an electronic control unit of said washing machine; wherein said actuator or motor is fixed on said shell and is separate from said drawer, and wherein said at least one pumping member (18a, 18b) is able to assume: - an active condition, in which said pumping member (18a, 18b) is coupled to said actuator or motor and to said at least one passage (17a, 17b), thus allowing said quantity of washing agent to be dispensed, when said drawer is in said retracted position, and - an inactive condition, in which said pumping member (18a, 18b) is uncoupled from at least one between said actuator or motor and said at least one passage (17a, 17b), thus preventing said quantity of washing agent from being dispensed, when said drawer is in said extracted position; said structure further comprising: - a plurality of said chambers (16a, 16b), - a plurality of said passages (17a, 17b), each one of them being associated with a respective chamber (16a, 16b), and - a plurality of pumping members (18a, 18b), each one of them for being hydraulically coupled to a respective passage (17a, 17b); said structure being characterised in that it comprises a single actuator or motor which, in turn, comprises a plurality of output members (22a, 22b) and a transmission mechanism arranged for selectively controlling the power delivered by the output members (22a, 22b) to the respective pumping members (18a, 18b); in that said transmission mechanism is of the clutch type and is fit for selectively activating said output members (22a, 22b) in an electrically controlled manner; and in that said transmission mechanism comprises an oscillating lever which tends to elastically hold in an engaging manner an output shaft with said single electric motor; said oscillating lever being adapted to be moved so as to engage the other output shaft due to the action of an electromagnetic actuator, which is suited to be electrically supplied with power by said electronic control unit of the washing machine and is designed to push said oscillating lever. - a hollow shell intended to be fitted on a casing of said washing machine; - a drawer defining at least one chamber (16a, 16b) for receiving a washing agent and mounted so as to move in said shell between an extracted position, in which said at least one chamber (16a, 16b) is able to be accessed from the outside and is ready to receive said washing agent, and a retracted position, in which said at least one chamber (16a, 16b) is closed by said shell and arranged for dispensing said washing agent to the outside of said structure; - at least one passage (17a, 17b) which communicates, on one side, with said at least one chamber (16a, 16b) and, on the other side, with the outside of said structure; - at least one pumping member (18a, 18b) arranged for driving a quantity of said washing agent from said at least one chamber (16a, 16b) through said passage (17a, 17b); and - an actuator or electric motor arranged for operating said at least one pumping member (18a, 18b) and for being connected to an electronic control unit of said washing machine; - an active condition, in which said pumping member (18a, 18b) is coupled to said actuator or motor and to said at least one passage (17a, 17b), thus allowing said quantity of washing agent to be dispensed, when said drawer is in said retracted position, and - an inactive condition, in which said pumping member (18a, 18b) is uncoupled from at least one between said actuator or motor and said at least one passage (17a, 17b), thus preventing said quantity of washing agent from being dispensed, when said drawer is in said extracted position; - a plurality of said chambers (16a, 16b), - a plurality of said passages (17a, 17b), each one of them being associated with a respective chamber (16a, 16b), and - a plurality of pumping members (18a, 18b), each one of them for being hydraulically coupled to a respective passage (17a, 17b);