  The likely presence of $\Lambda$ baryons in dense hadronic matter tends to
soften the equation of state to an extend that the observed heaviest neutron
stars are difficult to explain. We analyze this "hyperon problem" with a
phenomenological approach. First, we review what can be learned about the
interaction of $\Lambda$ particle with dense matter from the observed
hypernuclei and extend this phenomenological analysis to asymmetric matter. We
add to this the current knowledge on non-strange dense matter, including its
uncertainties, to conclude that the interaction between $\Lambda$s and dense
matter has to become repulsive at densities below three times the nuclear
saturation density.
