  Binary stars are places of complex stellar interactions. While all binaries
are in principle converging towards a state of circularization, many eccentric
systems are found even in advanced stellar phases. In this work we discuss the
sample of binaries with a red-giant component, discovered from observations of
the NASA Kepler space mission. We first discuss which effects and features of
tidal interactions are detectable in photometry, spectroscopy and the seismic
analysis. In a second step, the sample of binary systems observed with Kepler,
is compared to the well studied sample of Verbunt & Phinney (1995, hereafter
VP95). We find that this study of circularization of systems hosting evolving
red-giant stars with deep convective envelopes is also well applicable to the
red-giant binaries in the sample of Kepler stars.
