The problems of light propagation and scattering in twisted nematic and cholesteric liquid crystals are considered. We study the correlation function of the director fluctuations, the eigenwaves, and the Green’s function for helical liquid crystals with the pitch, which significantly exceeds the wavelength of light. The obtained results make possible to describe angular and polarization dependencies in scattered light, the wave-guide channel formation, the turning points and the effect of percolation through the forbidden zone.