Objectives : This study was performed to investigate the antifatigue effect of SM-2000 on fatigued and stressed people. Methods : This study was carried out on 23 healthy people who have fatigue and stress. 11 people as the mentally-stressed group were examined by subjective symptoms of fatigue and blood cortisol test. They drank SM-2000 for seven days. SM-2000 was made up herbs which were used for fatigue. After that they were again examined by subjective symptoms of fatigue and blood cortisol test. 12 people as the physically-fatigued group were examined with fatigue biomarkers and exercise test. They also drank SM-2000 for seven days. After that they were again examined with fatigue biomarkers and exercise test. Results : Cortisol level, subjective symptoms of fatigue scores and physical, mental, and neuro-sensory symptoms of fatigue scores after drinking SM-2000 were not significantly increased compared with before drinking SM-2000 in the mental stressed group. SM-2000 significantly decreased lactate, glucose, and phosphorous levels, and running time after drinking SM-2000 was significantly suppressed compared with before drinking SM-2000 in the physically-fatigued group. Conclusions : On the basis of these results, SM-2000 had a clinical antifatigue effect in physically-fatigued people.