The phenomenon of drag in turbulent flows causes a significant pressure drop for the transportation of any fluid, which increases the energy required to promote the flow. This is why studies on Drag Reduction (DR) were originated, which can occur by adding surfactants, fibers, or polymers to the solvent fluid. Its use has records that exceed sixty years and are already applied in firefighting [24], transportation of various fluids [25] and even to increase the speed of vessels [26]. This work aims to verify and quantify the effectiveness of the addition of polymeric materials on drag reduction and on the transition of regimes in two-phase gasliquid flow in turbulent regime, through horizontal pipes. The motivation for the work is the possible reduction of friction in oil and gas pipelines in the two-phase regime. To this end, the experiments employed measurements of pressure drop, flow rate and void fraction to characterize the effects of adding a friction reducer to the flow of air and water in the slug regime. The tests were conducted for a Reynolds number range of 20,000 to 103,000, in a combined experimental array for three given water and air flow rates. The polymer used was Guar Gum, at concentrations of 400ppm and 600ppm, dissolved in distilled water. The flow with this additive showed a maximum drag reduction around 35 percent for the single-phase regime and 20 percent for the two-phase regime. The addition of the polymer did not show much influence on the transition of flow regimes, as there were no significant changes for the average values of frequency, velocity, and liquid piston length.