  The recombination history of the Universe provides a useful tool for
constraining the annihilation of dark matter particles. Even a small fraction
of dark matter particles annihilated during the cosmic dark age can provide
sufficient energy to affect the ionization state of the baryonic gas. Although
this effect is too small for neutralinos, lighter dark matter particle
candidates, e.g. with mass of 1-100 MeV, which was proposed recently to explain
the observed excess of positrons in the Galactic Center, may generate
observable differences in the cosmic microwave background (CMB) temperature and
polarization anisotropies. The annihilations at the era of recombination
affects mainly the CMB anisotropy at small angular scales (large $\ell$), and
is distinctively different from the effect of early reionization. We perform a
multi-parameter analysis of the CMB data, including the both the WMAP first
year and three year data, and the ACBAR, Boomerang, CBI, and VSA data. Assuming
that the observed excess of $e^+e^-$ pairs in the galactic center region is
produced by dark matter annihilation, and that a sizable fraction of the energy
produced in the annihilation is deposited in the baryonic gas during
recombination, we obtain a %95 dark matter mass limit of $M<8 \MeV$ with the
current data set.
