The triple-to-double ionization cross-section ratio of Li in the high-energy limit was computed in the sudden approximation with relativistic wave functions. Together with the calculated value of Dalgarno and Sadeghpour (Phys. Rev. A, 46 (1992) R3591), for the Li double-to-sirigle ionization cross-section ratio, the value of 6.263 × 10-5 was obtained for the triple-to-single ionization cross-section ratio. This value is in full agreement with Wehlitz et al. experimental value of (6.38 ± 2.40) × 10-5 obtained recently with synchrotron radiation (Phys. Rev. Lett., 81 (1998) 1813).