Fibromyalgia (FM) is a syndrome characterized by chronic and widespread musculoskeletal pain, fatigue sleep disturbances and cognitive and somatic symptoms. It is commonly conjectured that central sensitization is physiological hallmark of FM. Therefore, centrally acting medications including antidepressants and anticonvulsants are used to treat FM via downregulating dorsal horn sensitization and systemic hyperexcitability.However, those drugs are limited in clinical practice resulting from dose-limiting adverse effects and incomplete drug efficacy.Shugan Dingtong decoction(SGDTD) is a Chinese herbal formula and has been used for treatment of FM in clinical practice many years. However, few research can provide high-quality evidence on the efficacy and safety of SGDTD for the treatment of FM. Therefore, a parallel-group randomized controlled trial was designed to evaluate the efficacy and safety of SGDTD on FM.

Inclusion Criteria:

• patients aged 18-70 years old.
• patients who meet the diagnostic criteria of American College of Rheumatology in 2016.
• patients who meet the diagnostic criteria of Syndrome of stagnation of liver qi.
• pain scores between3 and 7 on visual analogue scale.
• patients sign the informed consent forms.

Exclusion Criteria:

• pregnant and lactating women.
• patients with serious primary diseases of respiratory, digestive, urinary, cardiovascular and immune system.
• patients with mental and psychological disorders including cognitive im-pairment, severe depression, somatoform disorders.
• patients with secondary fibromyalgia resulted from osteoarthritis, rheumatoid arthritis, trauma, hypothyroidism, malignant tumor.
• patients with severe pain resulted from diabetic and postherpetic neuralgia.
• patients who are allergic to the drugs used in this study.
• patients are participation in any other clinical trials or receive other drugs for the treatment of fibromyalgia.