  The total lepton asymmetry $l=\sum_f l_f$ in our universe is only poorly
constrained by theories and experiments. It might be orders of magnitudes
larger than the observed baryon asymmetry $b\simeq {\cal O}(10^{-10})$, $|l|/b
\leq {\cal O}(10^{9})$. We found that the dynamics of the cosmic QCD transition
changes for large asymmetries. Predictions for asymmetries in a single flavour
$l_f$ allow even larger values. We find that asymmetries of $l_f\leq {\cal
O}(1)$ in a single or two flavours change the relic abundance of WIMPs.
However, large lepton and large individual lepton flavour asymmetries
influences significantly the dynamics of the early universe.
