RESUMEN
The present study was undertaken in twenty young, healthy Thai males to investigate the effects of prolonged administration of standardized ginseng extract on peripheral blood leukocytes and lymphocyte subsets. The subjects were divided into two equal groups as ginseng and placebo groups. The first group received two capsules daily of standardized ginseng extract 150 mg per capsule for 8 weeks. The second group received placebo and served as control. Circulatory levels of total and differential leukocyte counts and percentage of lymphocyte subsets were determined prior to and at the 4th and 8th week of the experimental period. There were no significant differences in the total and differential leukocyte counts as well as the lymphocyte subpopulations: CD3 (T cells), CD 19 (B cells), CD4 (T-helper cells), CD8 (T-suppression cells), CD4/CD8 ratio, and CD25 (Interleukin-2-receptor cells) between the two subject groups throughout the experimental period. We concluded that oral administration of standardized ginseng extract, 300 mg/day for 8 weeks caused no significant changes in peripheral blood leukocytes and lymphocyte subsets in young, healthy Thai males.