Vacuum symmetry and the pseudo-Goldstone phenomenon

In the context of gauge theories with spontaneous symmetry breakdown induced by the Higgs phenomenon, a simple theorem is stated which gives conditions under which pseudo-Goldstone particles may occur. These conditions are broader than the occurrence of accidental symmetry and contain the latter case as a special instance. We analyze an example in which the gross features of the vector- and the scalar-meson mass spectra are determined by quantum effects.