Yarrow (Achillea millefolium) has a long history of use in traditional herbal medicine, particularly in Europe and Asia, for supporting the female reproductive system. Traditionally, yarrow has been used to manage menstrual discomfort, regulate menstrual cycles, and address excessive menstrual bleeding (menorrhagia). Folk herbalists have employed yarrow as an emmenagogue (an herb that stimulates menstrual flow) and as an astringent for its purported ability to tone uterine tissues and reduce heavy bleeding. Preparations of yarrow, including teas and tinctures, were commonly recommended for women experiencing irregular or painful periods, as well as for postpartum recovery.

Modern scientific evidence for these specific uses is limited. There are a few laboratory and animal studies indicating anti-inflammatory, antispasmodic, and astringent properties in yarrow extracts, which could theoretically support its traditional applications for menstrual discomfort and bleeding. However, there is a lack of robust clinical trials directly validating yarrow's efficacy for female reproductive health in humans. Most of the support for yarrow’s use in the female reproductive system remains anecdotal and rooted in traditional practice rather than established by scientific research.

In summary, yarrow’s reputation as a supportive herb for women's reproductive health is primarily based on traditional usage, with only minimal scientific evidence to support these applications.