BACKGROUND: Cancer-related fatigue is one of the most prevalent symptoms that patients with cancer experience, but the mechanisms underlying it are unknown. We aimed to quantify and mechanistically evaluate the improvement in fatigue related to administration of the Kampo medicine, Kamikihito. MATERIALS AND METHODS: Initially, we recruited outpatients with urological diseases and compared fatigue levels of 37 patients with cancer with a control group of 23 volunteers who had recovered completely from cancer or who were being treated for dysuria. Fatigue level was estimated using an autonomic function analyzer. Then, Kamikihito was administered to another 35 patients treated with hormone or antitumor therapy for prostate cancer and metastatic renal cell cancer. Subjective fatigue and other problems of the patients were assessed using the Chalder fatigue scale, the Center for Epidemiologic Studies Depression scale, and the Epworth sleepiness scale. Serum levels of derivatives of reactive oxygen species and biological antioxidant potential were also measured. RESULTS: Patients in the cancer treatment group experienced more fatigue compared with the control patients when evaluated using an autonomic function analyzer. The group of 35 patients who were administered Kamikihito showed improved scores for fatigue, depression, and sleepiness. Autonomic nervous system balance was also improved with Kamikihito administration. The Kamikihito group also had significantly lower reactive oxygen species metabolite levels and significantly higher antioxidant potential. CONCLUSIONS: Fatigue was more serious in patients with cancer than in control patients. Kamikihito rescued this fatigue and improved anxiety and sleepiness. It restored autonomic nervous system balance and antioxidant function.
