  Radio-loud AGNs can inhabit regions with a very rich ISM. The presence of
this rich medium is likely related to the origin and evolution of the host
galaxy and of the active nucleus. Recent observations show that a large
fraction of radio galaxies contains a significant young stellar population.
This supports the idea that mergers are responsible for both the starburst
phase and the triggering of the nuclear activity. The gas that reaches the
central regions can have quite disturbed kinematics, likely due to the effects
of the AGN activity and in particular of the powerful radio jets. The recent
detection of fast nuclear gas outflows, observed both in ionised and neutral
gas, is giving new and important insights into the physical conditions of the
gaseous medium around the nucleus and the interaction between the AGN and this
medium. Finally, as another example of the interplay between the radio activity
and the ISM, the possibility of star formation induced by the passage of the
radio jet will be discussed.
