Herbkines has been used for the purpose of development of physical strength. In the present study, we investigated the effect of Herbkines on performance of the forced swimming test (FST) and on blood biochemical parameters related to fatigue: blood urea nitrogen (BUN), creatine kinase (CK), lactic dehydrogenase (LDH), glucose (Glc), and total protein (TP). Herbkines were orally administered to mice, 10 ml/kg, continuously once per day for 2 weeks using a feeding atraumatic needle. After 2 d, on FST, the immobility time was decreased in the Herbkines-fed group (178+/-8.2 s) in comparison with the control group (189+/-22 s); however, the statistical difference was very weak (p=0.596). After 2 weeks, the immobility time was significantly decreased in the Herbkines-fed group (196+/-4.5 s) in comparison with the control group (221+/-6.2 s). In addition, the content of BUN in the blood serum was significantly decreased. However, the levels of CK, LDH, Glc, and TP did not show a significant change. The results predict a potential benefit of Herbkines as an anti-fatigue treatment and for improving physical stamina.