Abstract: An exhaust gas scrubber includes a closed tank partially filled with a pool of water and a core assembly within the tank. The assembly includes a vertical cylindrical mixing tube open at its opposite ends and extending above and below water level, an upwardly opening cylindrical deflector cup at the bottom of the tank with its opening concentrically spaced within the lower end of the mixing tube, and a downwardly opening cylindrical deflector hood concentrically receiving the upper end of the mixing tube. Exhaust gases are introduced into the tank through a gas inlet tube, which extends downwardly concentrically through the deflector hood and mixing tube to discharge the gases through its open lower end into the cup. The gases are deflected upwardly into an annular mixing and expansion chamber within the mixing tube through an annular gas orifice defined by an upper side wall of the cup and lower side wall of the inlet tube.