The particular non-Newtonian fluid under consideration is an incompressible dilute polymer solution. It has long been known experimentally that certain dilute polymer solutions may exhibit a significant reduction in turbulent drag (Ellis, 1970). Thus, understanding the behaviour of such fluids under turbulent conditions is of great importance. It is our aim to probe the basic dynamic properties of a dilute polymer solution, without any dependence on solid boundary conditions. Our approach is to study different non-Newtonian equations, corresponding to different polymer solution models, via the direct numerical simulation of homogeneous isotropic turbulence. In this way we have identified changes within the structure of turbulence itself which may be related to the 'drag reduction' phenomenon.