Rotation and Abundances in Red Giants

The abundances of red giants will be reviewed, in particular those of carbon, nitrogen, oxygen and 12C:13C. The observed abundances are compared to predictions based on recent models with stellar rotation. Three topics will be emphasized: abundances in very metal-poor stars related to a previous generation of supernova; 12C:13C in red giants and rotation induced extra mixing; CNO abundances in yellow supergiants and their connection with models computed with rotation.