[en] The effects of multiple internal rotations on the ¹³C--]¹H] nuclear Overhauser enhancement (NOE) and ¹³C spin lattice relaxation has been considered. It is shown that the 5 x 5 matrices which arise from a treatment using the Wigner rotation matrices of order 2 can be replaced by 3 x 3 matrices by making use of the inherent symmetry of the problem without any loss of generality. The cross correlations which arise in chains of methylene carbons are also taken into account. Calculations are given for the NOE values for carbons in a methylene chain for several values of the internal diffusion coefficients D/sub i/, assumed constant along the chain, as a function of D₀. It is found that the effect of cross correlations on the NOE values is relatively small except in the region where the isotropic diffusion coefficient of the end of the chain satisfies the condition 6D₀approx.ω/sub c/. In this region the effect of cross correlations depends on the internal diffusion coefficient D/sub i/, being insignificant for D/sub i/=10⁹ sec^-1 and somewhat more important for D/sub i/=10¹⁰ and 10¹¹ sec^-1. The spin lattice relaxation is also most markedly nonexponential in the region where 6D₀approx.ω/sub c/. As D₀ increases or decreases beyond this value the relaxation becomes more exponential. The effect of the isotropic D₀ motion on both the NOE and the spin lattice relaxation decreases rapidly for carbons further from the isotropically tumbling end of the molecule. An example involving a galactolipid phospholipid suspension is briefly discussed