The Herb Cabinet 本草

牡丹皮 mǔ dān pí

Paeonia suffruticosa · tree peony root bark

Slightly cold Bitter · Pungent HeartLiverKidney

“The king of flowers keeps a cooling medicine in its root bark. For heat that hides in the blood and flares at night, this is the quiet extinguisher.” — Lao Xinglin

What the tradition says

The tree peony — mu dan, "king of flowers" — gives medicine from below the throne: its root bark cools the blood and moves the blood at once^[1]. The classic callings are heat smoldering in the blood level: nosebleeds and rashes, night-time fevers, and the "steaming bone" heat of yin deficiency — plus the stasis side: masses, injuries, and painful menstruation^[1]. In Liu Wei Di Huang Wan it is the assistant that damps the flickering fire of depletion while the tonics refill the lamp; in Jia Wei Xiao Yao San it cools what constraint has overheated.

What the research says

Paeonol, the bark's fragrant marker compound, is a busy laboratory subject — anti-inflammatory and microcirculatory signals in animal models — without independent clinical trials of the bark itself. Its evidence lives inside the formulas it serves.

Where to be careful

A cooling blood-mover's standard fences: the tradition withholds it in pregnancy, in cold-pattern conditions, and in heavy menstruation without stasis signs^[1].

In the pharmacy

Quilled strips of grey-brown bark with a sweet-medicinal fragrance (paeonol announcing itself), stripped from the roots of garden tree peonies after the flowers have had their fame^[1].

Reviewed 2026-08-26