Agrimonia pilosa, commonly known as hairy agrimony, has a long history of use in traditional medicine systems across East Asia, particularly in Chinese, Korean, and Japanese herbal medicine. In traditional Chinese medicine (TCM), it is classified as an herb that “stops bleeding” (hemostatic), and is commonly used to treat various forms of internal bleeding such as hematemesis (vomiting blood), hematuria (blood in urine), and metrorrhagia (uterine bleeding). The dried aerial parts of the plant are typically prepared as decoctions or powders for this purpose.

The rationale for its hemostatic effects in traditional medicine is attributed to its purported ability to astringe and contract tissues, thereby reducing bleeding. Modern phytochemical studies have identified compounds such as flavonoids, tannins, and agrimoniin in Agrimonia pilosa. Tannins in particular are known to have astringent properties, which could theoretically contribute to reducing bleeding by promoting vasoconstriction and coagulation. However, while some in vitro and animal studies suggest mild hemostatic effects, robust clinical data in humans are lacking. Thus, its use for internal bleeding is primarily supported by traditional use and limited preclinical evidence, but not by high-quality clinical trials.