  An original method of estimating the projected rotational velocity, $vsini$,
and the macroturbulent velocity, $v_{\rm mac}$, of evolved M giant stars is
presented. It is based on the use of spectrum synthesis and multi-line analysis
tools. The goal is to fit the mean line profile of observations with that of
synthetic spectra. The method is applied to the red giant star RZ Ari and the
results $v\sin i$ = 6.0 $\pm$ 0.5 km/s and $v_{\rm mac}$ = 2.0 $\pm$ 1.0 km/s
are obtained.
