Lithium and the carbon isotope ratio ^12^C/^13^C can change during the red giant branch as a result of extra-mixing. This is associated usually with thermohaline mixing acting after the RGB bump. Peculiar Li-enriched RGB stars might also be related to either enhanced extra-mixing or pollution from external sources. We measure the Li abundance and ^12^C/^13^C in a sample of 166 field giants targeted by the EXPRESS radial velocity program to analyze the effects of extra-mixing. We measure the abundances with spectral synthesis using high-resolution and high signal-to-noise spectra. Multiple-epoch observations needed for exoplanet detection are used to decrease the effects of telluric contamination in ^12^C/^13^C measurements.