A comparatives study about the efficiency of five commercial products used to facilitate the transport of oil through pipelines was developed using a new experimental mental technique. The technique is based oil the applied torque necessary to keep the samples rotating in turbulent flow. The hydrodynamic drag reduction is proportional to the difference on the torque applied in oil samples with and without the additive. The experiments were developed in a Couette cell of a rheometer, which is sensitive to determine levels of drag reduction with high accuracy. The method was tested by using five commercial samples of drag reducers added to a Brazilian oil sample. Their efficiency, as well as their optimum concentrations, was compared. The method has proven very attractive mainly due to the low amount of sample and the short time required for the measurements.