  Thermohaline mixing has recently been proposed to occur in low mass red
giants, with large consequences for the chemical yields of low mass stars. We
investigate the role of thermohaline mixing during the evolution of stars
between 1Msun and 3Msun, in comparison to other mixing processes acting in
these stars. We confirm that thermohaline mixing has the potential to destroy
most of the ^3He which is produced earlier on the main sequence during the red
giant stage. In our models we find that this process is working only in stars
with initial mass M <~ 1.5Msun. Moreover, we report that thermohaline mixing
can be present during core helium burning and beyond in stars which still have
a ^3He reservoir. While rotational and magnetic mixing is negligible compared
to the thermohaline mixing in the relevant layers, the interaction of
thermohaline motions with differential rotation and magnetic fields may be
essential to establish the time scale of thermohaline mixing in red giants.
