This study was done to evaluate the immune enhancing activity of health function food, chitosan by clinical study. To evaluate the effect of chitosan on serum cytokine levels in elderly adults, 5.1 g/day of chitosan was administrated to volunteers (age range $74{sim}86$, mean $80{pm}3$ year old) for 8 weeks. This study was IRB approved and all patients gave informed consent prior to examination. The clinical study showed that the increase of IL-2, IL-12, and $TNF-{alpha}$, production were a little greater in chitosan administered group as in the control group but there were no significant differences. In the safety study with blood biochemical test, it has been shown that all safety parameters in liver were in normal ranges. Also there were no significant changes in the values of the electrolytes, blood lipids profiles, glucose levels and leucocytes number. With these results we have not found any safety problems after the administration of chitosan for 8 weeks. In this study, there was a tendency of immune enhancing effect of chitosan at the experimental dose, which is generally used. More intense clinical study will be needed to confirm statistical significance.