  The issues of quintessence and cosmic acceleration can be discussed in the
framework of theories which do not include necessarily scalar fields. It is
possible to define pressure and energy density for new components considering
effective theories derived from fundamental physics like the extended theories
of gravity or simply generalizing the state equation of matter. Exact
accelerated expanding solutions can be achieved in several schemes: either in
models containing higher order curvature and torsion terms or in models where
the state equation of matter is corrected by a second order Van der Waals
terms. In this review, we present such new approaches and compare them with
observations.
