3Results 3.1. Description of included trialsThe searches identified 746 potentially relevant studies, ofwhich three met our inclusion criteria (Fig. 1). The key data fromall included RCTs are summarized in Table 1. Three RCTs originatedfrom China [31–33] and one from Japan [34]. The three trials eval-uated 435 women with primary dysmenorrhea. Modified DSS wasused alone in three trials [31–33], and DSS was combined with