Both water- and oil-soluble linear polymers with high molecular weights are known to decrease the frictional drag in turbulent flows very effectively at concentrations of tens or hundreds of ppm. Such dilute polymer solutions undergoing flow in a pipe require a lower pressure drop to maintain the same volumetric flow rate with up to more than 80% of energy saving. This polymer-induced drag reduction efficiency is well known to be closely associated with the flow conditions and rheological, physical, and/or chemical characteristics of the polymers added. The polymeric species including both synthetic and natural polymers such as poly(ethylene oxide), polyacrylamide, poly(isobutylene), and DNA, mechanical degradation of polymer under turbulence, and mechanism will be covered along with their various applications.