  The influence of the irregular forces on the evolution of a triple
hierarchical stellar system moving in the field of stars have been studied.
Triple hierarchical stellar systems are stable in contrary to the stellar
systems with comparable distances between all components. We considered the
motion in the frame of the general tree-body problem using differential
equations of the motion with the Hamiltonian without short-periodic terms.
  For isolated triple stellar systems, where we took into account the
perturbations until the third order, we obtained the solution in which the mean
motions of both components have the secular accelerations. Under the influence
of perturbations of the distant component the mean motion in the near pair is
slowed and vice versa. The mean motion of the distant star is constantly
increasing. These changes are small, but on the cosmological time interval the
hierarchical systems will convert into stellar systems, in which all components
have comparable distances between each other. Such systems become unstable.
  In a general case, if we take into account the irregular forces, the angular
momentum of this system and its summary energy might be either loss or gain.
These changes may influence on the dynamical evolution and stability of the
stellar system.
