Chronic fatigue is a common symptom in primary health care and caused by various organic and functional diseases. Although improvement is attained by controlling underlying organic disease, it is sometimes difficult to relieve fatigue in patients with chronic fatigue syndrome or dysthymia. We have encountered patients with idiopathic chronic fatigue (ICF) successfully treated with sansonintokagen. A 62-year-old female complained of chronic fatigue several years after menopause, and had normal status in routine blood and image analyses at a nearby hospital. Her condition was diagnosed as ICF with sleeplessness. Treatment with sansonintoaogibakumondo for 8 weeks improved her chronic fatigue and sleeplessness, and enabled her to continue housekeeping. This observation suggests that this kampo formula may be a useful agent for ICF.