A shampooing tool has a "clam-shell" design for trapping the components of the tool between the complementary mating halves of the housing. The components include a barrel disposed in the upper portion of the housing and connected to a pressurized water source, a trigger depending from an enclosed hand grip, a normally-closed spring-loaded valve disposed in the front portion of the housing and connected to the trigger for movement in unison, and a cylinder within the lower part of the housing, the cylinder having a pressurized liquid detergent and further having a discharge port leading to a valve seat. When the trigger is depressed, the valve is unseated; and the liquid detergent, under pressure, flows into a tube running substantially parallel to the barrel. A shampooing head on the end of the barrel has first and second orifices connected to the barrel and to the tube, respectively; and the respective first and second orifices are independent of each other and are arranged intermediately of the bristles on the shampooing head. The shampooing tool is intended, primarily, for dogs, horses or other animals.