Purpose: The purpose of this case study is to report the effect of Mahwang-tang (MHT) on fibromyalgia based on Shanghanlun Provisions. Methods: According to diagnostic system based on Shanghanlun provisions, the patient was diagnosed with Taeyang-byung and treated by MHT. The result of administrations were evaluated by Numeral Rating Scale (NRS), Widespread Pain Index (WPI), Symptom Severity Scale (SSS) score and change of clinical symptoms. Results: After administration of MHT for 70 days, NRS improved from 8 to 3, SSS improver 8 to 4, WPI 13 to 12. In provision 35, ‘風’ means a nervous system disease that moves around the entire body as if sailing and ‘通’ does not mean simple pain, but pain that contains anxiety. No serious treatment-related adverse events were reported. Conclusion: This study shows the effective treatment of fibromyalgia using MHT based on Shanghanlun provisions.