Achyranthes bidentata (commonly known as “Niu Xi” in Traditional Chinese Medicine) is traditionally used to support or treat menstrual irregularity. Its use is rooted primarily in the practices of Traditional Chinese Medicine (TCM), where it is believed to invigorate blood circulation, dispel blood stasis, and regulate menstruation. Classical TCM texts and modern Chinese herbal compendia list Achyranthes bidentata as a component in various formulas for menstrual disorders such as amenorrhea, dysmenorrhea, and irregular menstruation.

However, scientific validation is limited. Most available evidence comes from animal studies and in vitro experiments, which suggest that extracts of Achyranthes bidentata may influence uterine smooth muscle contraction and possess anti-inflammatory or analgesic effects. There are a few small clinical studies in Chinese literature, but these are often of low methodological quality, lack controls, or combine Achyranthes bidentata with other herbs, making it difficult to attribute observed effects specifically to this plant.

In summary, the use of Achyranthes bidentata for menstrual irregularity is primarily traditional, and while some preliminary pharmacological data exist, robust clinical evidence is lacking. The evidence level is best rated as 2 out of 5, reflecting strong traditional support but weak scientific validation.