  In this talk I comment on the contributions of all three types of particles
(scalars, fermions and bosons) to the three--photon Z decay within the standard
model (SM) and its extensions to the 2 Higgs doublet model (2 HDM) and the
minimal supersymmetric extension of the standard model (MSSM). I also comment
briefly on the charginos contribution to this decay rate. Finally I comment on
the fermions and scalars contributions to the three--gluon Z decay.
