  We combine complementary datasets to constrain dark energy. Using standard
Big Bang Nucleosynthesis and the observed abundances of primordial nuclides to
put constraints on $\Omega_Q$ at temperatures near $T \sim 1MeV$, we find the
strong constraint $\Omega_Q({MeV}) < 0.045$ at $2\sigma$ c.l.. Under the
assumption of flatness, using results from Cosmic Microwave Background (CMB)
anisotropy measurements, high redshift supernovae (SN-Ia) observations and data
from local cluster abundances we put a new constraint on the equation of state
parameter $w_Q < -0.85$ at 68% c.l..
