['Few studies have investigated the effects produced by combinations of polysaccharides and chemotherapeutic drugs in cancer treatment. We hypothesized that a combination of polysaccharides (COP) from Lentinus edodes and Tricholoma matsutake would improve the efficacy of 5-fluorouracil (5-FU)-mediated inhibition of H22 cell growth.', 'Mice were injected H22 cells and then treated with either 5-FU, polysaccharides from Tricholoma matsutake (PTM), polysaccharides from Lentinus edodes (PL), PTM+PL, 5-FU+PTM, 5-FU+ PL, or 5-FU + COP. The tumor weight and volume, and splenic CD4 + and CD8 + T cell frequencies, were determined. Additionally, splenic natural killer (NK) cell and cytotoxic T lymphocyte (CTL) activities were assessed and the serum levels of tumor necrosis factor-alpha (TNF-alpha), Interleukin-2 (IL-2), and Interferon-gamma (IFN-gamma) were measured.', 'Compared with mice from the control, 5-FU, PL, PTM, PTM + PL, 5-FU + PL, and 5-FU + PTM groups, mice treated with 5-FU + COP showed: (a) significantly reduced tumor weight and volume (P < 0.05); (b) significantly higher serum levels of TNF-alpha, IL-2, and IFN-gamma (P < 0.05); (c) significantly increased CD4+ and CD8+ T cell frequencies in the spleen (P < 0.05); and (d) significantly increased splenic NK cell and CTL activities (P < 0.05). The tumor weight and volume in mice treated with 5-FU+PL or 5-FU+PTM were significantly reduced compared with mice treated with 5-FU alone (P < 0.05). Serum levels of TNF-alpha, IL-2, and IFN-gamma, frequencies of CD4 + and CD8+ T cells in the spleen, and splenic NK and CTL activities were also significantly increased in mice treated with 5-FU+PL or 5-FU+PTM compared with mice treated with 5-FU alone (P < 0.05).'] Do polysaccharides from Tricholoma matsutake and Lentinus edodes enhance 5-fluorouracil-mediated H22 cell growth inhibition?