  We explore effects of the Shakura-Sunyaev alpha-viscosity on the dynamics and
oscillations of slender tori. We start with a slow secular evolution of the
torus. We show that the angular-momentum profile approaches the Keplerian one
on the timescale longer than a dynamical one by a factor of the order of
1/\alpha. Then we focus our attention on the oscillations of the torus. We
discuss effects of various angular momentum distributions. Using a perturbation
theory, we have found a rather general result that the high-order acoustic
modes are damped by the viscosity, while the high-order inertial modes are
enhanced. We calculate a viscous growth rates for the lowest-order modes and
show that already lowest-order inertial mode is unstable for less steep angular
momentum profiles or very close to the central gravitating object.
