In this research the flow of Newtonian and drag reducing fluids through a helical tube,i.e.. Dean’s flow, was experimentally studied. The primary concern was to investigate the effect of added polymer on the secondary motion caused by the centrifugal force. The poiymer chosen in this study was poly(ethylene oxide) with the molecular weights of 300,000, 900,000 and 4,000,000 and the solvent was distilled water. The concentration range was 0 to 100 wppm. The Dean number investigated was in the range of 10 to 20,000. In the case of distilled water, the experimental data were in good agreement with the literature. In the case of polymer solutions, it was found that the secondary motion was supressed as the concentration and molecular weight increased. However, if the molecular weight or concentration exceeded certain values, the effects were saturated. The results were also analyzed from the view point of drag reduction phenomena.