  Thermohaline mixing has recently been proposed to occur in low mass red
giants, with large consequence for the chemical yields of low mass stars. We
investigate the role of thermohaline mixing during the evolution of stars
between 1 Msun and 3 Msun. We use a stellar evolution code which includes
rotational mixing and internal magnetic fields. We confirm that thermohaline
mixing has the potential to destroy most of the helium 3 which is produced
earlier on the main sequence during the red giant stage, in stars below
1.5Msun. We find this process to continue during core helium burning and
beyond. We find rotational and magnetic mixing to be negligible compared to the
thermohaline mixing in the relevant layers, even if the interaction of
thermohaline motions with the differential rotation may be essential to
establish the time scale of thermohaline mixing in red giants.
