The method of study the transport phenomena in many-component systems
with a conserving momentum is developed. The general expressions are o
btained for viscosity, thermoconductivity and diffusion coefficients o
f quasiparticles. The oscillations are also considered in such systems
. The damped waves are shown to be of the hydrodynamic nature. The met
hod devised was used to obtain the temperature dependence of attenuati
on of the second sound in a magnon gas.