Objective This study aimed to evaluate the safety of chitosan oligosaccharide-taurine aqueous solution for consumption and its effect on the immune function of mice.Methods Safety was evaluated through acute toxicity tests， a 28-day feeding toxicity study， and genotoxicity experiments. The immunomodulatory effects were determined by measuring delayed-type hypersensitivity （DTH）， lymphocyte proliferation capacity， hemolytic plaque count， serum hemolysin levels， monocyte-macrophage function， and NK cell activity.Results The acute toxicity test demonstrated that the LD₅₀ of a 3× concentrated chitosan oligosaccharide-taurine aqueous solution was greater than 30 000 mg/（kg·BW） （calculated by the amount of oral solution） in both female and male rat. According to acute toxicity classification standards， the sample is considered practically non-toxic. The 28-day feeding study revealed no adverse effects on general condition， body weight， food utilization， organ weight， or organ coefficients in any dose group. No abnormal ocular changes were observed. Urinalysis， hematological， and biochemical indicators all fell within normal ranges. Histopathological examination of organs showed no abnormalities related to the test substance. Genotoxicity tests， including the Ames test， mammalian erythrocyte micronucleus assay， and mouse spermatocyte chromosomal aberration test， all yielded negative results， indicating no mutagenic or teratogenic effects. The functional study results showed that after 30 days of oral administration at doses of 2.5， 5.0， and 10.0 mL/（kg·BW·d）， the chitosan oligosaccharide-taurine aqueous solution had no significant effects on mouse body weight or organ/body weight ratios.Compared with the negative control group， there were significant differences （P<0.05 or P<0.01） in the degree of toe swelling and the number of hemolytic plaques in the medium and high dose groups of mice， indicating that both the cellular and humoral immune test results of mice were positive；The results for monocyte-macrophage function and NK cell activity were negative.Conclusion This study demonstrates that the chitosan oligosaccharide-taurine aqueous solution exhibits a good safety profile and can modulate immune function in mice.Qbjective This study aimed to evaluate the safety of chitosan oligosaccharide-taurine aqueous solution for consumption and its effect on the immune function of mice.