  The effective Lagrangian including one loop corrections is deduced for the
couplings of the charged Higgs with quarks and leptons, and with charginos and
neutralinos. The effect of the one loop corrections is found to be quite
significant in a number of sectors. The effective Lagrangian is then used to
analyze the decay of the charged Higgs into a number of decay channels.
Specifically we consider the decay of $H^+(H^-)$ into the decay modes $t\bar b$
($\bar t b$), $\bar\tau\nu_{\tau}$ ($\tau \bar \nu_{\tau}$), and
$\chi_i^+\chi_j^0(\chi_i^-\chi_j^0)$ (i=1,2; j=1-4). The loop corrections to
these decay modes are also found to be quite significant lying in the range
20-30% in significant regions of the parameter space of the SUGRA model. The
effects of CP phases on the effective Lagrangian and on the branching ratios
are also analysed and these effects found to be important.
