This study examined the effect of pine needle distillate (Pinus densiflora Sieb. et Zucc) on the immune system and hematological parameters. C57BL/6 male mice weighing 20 ~21 g were divided into 3 groups and intraperitonially injected with either 200 $mu$L of saline (control), 50% diluted (P50) or 100% pine needle distillate (P100) once a day for 24 days. At the end of the experiment, the mice were anesthetized by ether and peripheral blood was collected from the femoral artery and the spleen was excised. Spleen weight decreased significantly (p<0.001) in the pine needle groups compared to the control group. The blood was used for a complete blood count and flow cytometrical analysis after immunofluorescence staining. The pine needle distillate dose-dependently decreased the CD4$^{＋}$/CD8 sup ＋/ ratio (p <0.05), and showed a tendency to increase the mean FSC (forward scatter) values of the CD8$^{＋}$T cells, while decrease the values of the CD4$^{＋}$T cells. There were no significant differences in WBC, RBC and platelet counts among the three groups, but hemoglobin and hemoglobin-related parameters and platelet volume increased and red blood cell volumes decreased with the administration of the pine needle distillate. These results suggest that the pine needle distillate may have immunosuppressive effects.