  We study the possibility to detect heavy physics effects in the interactions
of Higgs bosons and the top quark at future colliders using the effective
Lagrangian approach. The modification of the interactions may enhance the
production of Higgs bosons at hadron colliders through the mechanisms of gluon
fusion and associated production with a W boson or $t\bar{t}$ pairs. The most
promising signature is through the decay of the Higgs boson into two photons,
whose branching ratio is also enhanced in this approach. As a consequence of
our analysis we get a bound on the chromomagnetic dipole moment of the top
quark.
