Fluorescence correlation spectroscopy (FCS) was carried out for Rhodamine 6G (R6G) in aqueous solutions of saccharides. The autocorrelation function, G(t), exhibited binary decay. The slower and faster decays were ascribed to the diffusion of R6G molecules and to the fluorescence quenching due to intersystem crossing to the excited triplet state, respectively. The triplet state lifetime elongated in solutions with higher saccharide concentration, indicating slowdown of the oxygen diffusion.