In this paper, the influences of polymer structure on friction reduction effect are analysed. And then, a new kind of drag reducing additive (PSA), which nonpoisonous and eatable, is obtained by experiments and researches. The PSA additive is soluble readily in water and has good effect on drag reduction. No doubt, the PSA can be employed to reduce the frictional drag in turbulent flow systems of food-stuff liquids. And it is possible to exploit the potentiality of biomedical applications of the drag reducing agent (PSA) in future. We are convinced that PSA will make an immeasurable contribution to the fields of food-stuff and biomedicine.