  We discuss the relation between lepton number violation at high and low
energies, particularly, the constraints on baryogenesis models, which would be
implied by an observation of neutrinoless double beta decay. The primordial
baryon asymmetry can be washed out by effective lepton number violating
operators triggering neutrinoless double beta decay in combination with
sphaleron processes. A generic conclusion is that popular models of
baryogenesis are excluded if a non-standard mechanism of neutrinoless double
beta decay, i.e., other than the standard light neutrino exchange, is observed.
Apart from the effective field approach, we also outline the possible extension
of our arguments to a general UV-completed model.
