Previous studies showed that the symptoms of dysmenorrhea are closely related to the levels of serum NO and ET-1.24 As a vasodilator, NO can dilate blood vessels and regulate local vascular microcirculation.23 ET-1 is mainly expressed in uterine tissue and can exert significant vasoconstrictive and smooth muscle effects.24 In this study, the levels of ET-1 and NO in the FDC & SFZYD group were superior to those in the SFZYD group after the treatment. Here, EDN1 is linked to Dysmenorrhea.