  We set up sum rules for heavy lambda decays in a full QCD calculation which
in the heavy quark mass limit incorporates the symmetries of heavy quark
effective theory. For the semileptonic $\La_c$ decay we obtain a reasonable
agreement with experiment. For the $\La_b$ semileptonic decay we find at the
zero recoil point a violation of the heavy quark symmetry of about 20%.
