Paeonia moutan, commonly known as Moutan peony root or "Mu Dan Pi" in Traditional Chinese Medicine (TCM), has a long-standing traditional use for managing internal bleeding. In TCM, Mu Dan Pi is believed to "cool the blood" and "dispel blood stasis," making it a common ingredient in herbal formulations for conditions involving bleeding, such as hemoptysis (coughing blood), hematuria (blood in urine), and metrorrhagia (abnormal uterine bleeding). Classic medical texts such as the "Shennong Bencao Jing" and later compilations consistently mention its use for these purposes, and it is still included in many modern TCM protocols for disorders involving internal bleeding due to blood heat or stasis.

However, scientific validation for this specific use is limited. While some pharmacological studies have explored the anti-inflammatory, antioxidant, and anticoagulant properties of compounds isolated from Paeonia moutan (such as paeonol), there is little direct clinical or experimental evidence supporting its efficacy in treating or controlling internal bleeding in humans. Most of the available evidence is based on historical usage and practitioner reports rather than controlled clinical studies. Therefore, while the traditional rationale is strong, the scientific evidence remains inconclusive, justifying a moderate evidence rating.