Stellar Coronae with XMM-Newton RGS II. X-ray Variability

First results from high-resolution coronal spectroscopy of flares with the Reflection Grating Spectrometers on board the XMM-Newton satellite are reviewed. Rotational modulation in the X-ray light curve of HR 1099 is discussed. Results from time-dependent spectroscopy of flares in the active stars HR 1099, AB Dor, YY Gem are also presented. Variations in the shape of the emission measure distributions, in the abundances and in the average density of the cool plasma are discussed.