  To date, the presence of dark matter (DM) can be judged only by its
gravitational interaction on the visible matter. It is therefore important to
find the consequences of this interaction, which can then help to determine
both the DM properties and parameters and the dynamics and evolution of visible
matter. The gravitational influence of dark matter on the stability of
interstellar medium (ISM), the progenitor of stars and star clusters, was
considered. An isothermal self-gravity gas was taken as a suitable model
describing ISM, particles interacting only gravitationally were considered as
DM. The results obtained by analytical methods show that even a small amount of
fast DM particles significantly increases the stable radius of the gas cloud
and the corresponding mass while a higher relative density of DM destabilizes
the gas. It was shown that with typical parameters of ISM and DM, its presence
increases the maximum stable mass of isothermal cloud by a factor of four and
the radius by five.
