Using the mixing length theory we give expressions for turbulence pressure and the equation of state and various thermodynamic quantities when turbulence is included. On this basis we examined the size of turbulence in the evolution of two stars of masses 2.8 and 7.0 M from the main sequence to the red giant and the AGB stages, Our results show that in the late stages the turbulence pressure near the surface of the star can be as much as 30% of the total pressure.