  We searched for Na I D1,D2 interstellar absorption lines towards 12 giant
stars of the Sgr dwarf spheroidal and 3 stars of the associated globular
cluster Terzan 7, observed at high resolution with the UVES spectrograph at the
8.2 m Kueyen VLT telescope. These stars are not an ideal background source for
the analysis of interstellar (IS) absorption lines since they have been
observed in the framework of a stellar abundances study. However they are
sufficiently luminous to allow a decent S/N ratio at a resolution of about
43000, i.e. ~7 km/s, which allows an exploratory study. We detected two
distinct groups of IS absorptions, a ``local'' group, with radial velocities
ranging from -43 km/s to 50 km/s, and a high velocity group with radial
velocities ranging from 150 km/s to 165 km/s. Likely the high velocity
components are due to gas falling on the Sgr dSph since have been observed only
in 2 stars which are separated by only 1.5' in the sky. We argue that the
observations suggest a stripping of gas due to the passage of Sgr through the
Galactic disc.
