To evaluate the efficacy and safety of tacrolimus capsules in patients with myasthenia gravis who are inadequately treated by glucocorticoid.

Inclusion Criteria:

• diagnosed as myasthenia gravis (MG) by clinical diagnosis
• QMG scores ≥7 at the time of enrollment
• basic treatment drugs are mainly glucocorticoids, and the efficacy of glucocorticoid therapy was not sufficient

Exclusion Criteria:

• receiving blood purification therapy or immunoglobulin therapy within 8 weeks before the study
• QMG swallowing function score ≥ 2 points or QMG vital capacity = 3
• abnormal hepatic functions
• uncontrolled diabetes patients
• hyperkalemia patients
• immuno-inhibitors are forbidden due to malignancy, history of malignancy or history of HIV infection
• patients who are allergic to Tacrolimus or macrolide antibiotics
• receiving other immuno-inhibitors within 12 weeks