  We discuss an alternative approach to quintessence modifying the usual
equation of state of the cosmological fluid in order to see if going further
than the approximation of perfect fluid allows to better reproduce the
available data. We consider a cosmological model comprising only two fluids,
namely baryons (modelled as dust) and dark matter with a Van der Waals equation
of state. First, the general features of the model are presented and then the
evolution of the energy density, the Hubble parameter and the scale factor are
determined showing that it is possible to obtain accelerated expansion choosing
suitably the model parameters. We use the estimated age of the universe and the
data on the dimensionless coordinate distances to Type Ia supernovae and
distant radio galaxies to see whether Van der Waals quintessence is viable to
explain dark energy and to constrain its parameters.
