  In this letter we show a general description about flavor-changing neutral
currents (FCNC) mediated by scalars. The analysis is extended at two-loop level
for the Two-Higgs Doublet Model type-III because others models have strong
constraints on its parameters, even at high orders of the perturbation. For
this letter we focus on the standard model, calculating the amplitude for the
$h \to \gamma \gamma$ process and discussing the results briefly.
