Jiang Pi 姜皮 — Chinese Herbal Medicine

Jiang Pi (姜皮) At a Glance

• Herb: Jiang Pi
• Chinese name: 姜皮 (Jiang Pi)
• Latin name: Cortex Zingiberis (Dried Ginger Peel)
• Nature: Neutral
• Taste: Acrid, Bitter
• Meridian: Bladder
• Category: Treats eczema-sweet and bland/promotes diuresis

Jiang Pi (姜皮, Cortex Zingiberis) is the dried outer peel of ginger (Zingiber officinale Rosc.), distinguished from Sheng Jiang Pi (fresh ginger peel) by processing — Jiang Pi is the dried form, with a neutral rather than cool thermal nature. In classical TCM pharmacology, the peel of any medicinal plant is understood to act on the corresponding ‘skin’ level of the human body: ginger peel (whether fresh or dried) drains water from the skin and subcutaneous tissues, promoting urination and reducing oedema without the warming, diaphoretic action of the inner rhizome. Jiang Pi is a component of the classical Wu Pi San (Five Peel Powder), where it contributes its surface-water-draining action. Compared with Sheng Jiang Pi, the dried form is slightly less cooling and more focused on diuresis; compared with the ginger rhizome, it completely lacks the warming-Middle and antiemetic actions.

Actions & Therapeutic Effects

• Promotes urination and reduces oedema — drains water from the skin and subcutaneous tissues.
• Acts on surface water (皮水) — specifically treats mild subcutaneous oedema and facial puffiness.
• Harmonises the Spleen and promotes water metabolism — mild Spleen-harmonising function as part of the Wu Pi San synergy.
• Does NOT release the exterior or warm the Middle (unlike the rhizome).

Clinical Applications in TCM

• Mild generalised oedema and facial puffiness — Wu Pi San
• Oedema in pregnancy (with caution) — combined with Dong Gua Pi and Bai Zhu
• Nephrotic oedema with Spleen involvement — Wu Pi San with Fu Ling and Huang Qi
• Subcutaneous oedema from Dampness obstruction
• Post-surgical fluid retention — gentle diuretic support

Precautions & Safety

• Dosage: 3–10 g in decoction
• Contraindicated in fluid depletion or severe Yin deficiency
• Not interchangeable with Sheng Jiang or Gan Jiang — does not warm the Middle or release the exterior
• The diuretic action is mild — not a substitute for stronger diuretics when significant oedema is present
• Generally safe and well-tolerated

Classical TCM Formulas

• Wu Pi San (五皮散): Fu Ling Pi, Sheng Jiang Pi (or dried Jiang Pi), Da Fu Pi, Wu Jia Pi (or Sang Bai Pi), Chen Pi — drains water from the skin. Source: Hua Tuo Zhong Cang Jing.
• Jiang Pi Tang (姜皮汤): Jiang Pi as single herb decoction — for mild facial oedema.

Herb Combinations

• Jiang Pi + Fu Ling Pi (茯苓皮) + Sheng Jiang Pi (生姜皮): the ginger-poria peel synergy for surface oedema.
• Jiang Pi + Dong Gua Pi (冬瓜皮) + Chen Pi (陈皮): mild water-draining for Dampness-type facial puffiness.
• Jiang Pi + Bai Zhu (白术) + Fu Ling (茯苓): drains surface water while supporting Spleen function.

Pharmacology & Research

Mild diuretic: potassium content and flavonoids promote gentle diuresis.
Anti-inflammatory: gingerol-related compounds (lower concentration than rhizome) provide mild COX-inhibitory activity. The peel has proportionally higher fibre and mineral content than the flesh.

Classical Descriptions

• 《本草纲目》(Bencao Gangmu, 1596) — Li Shizhen: “姜皮，辛凉。消浮肿、腹胀、痞满，和脾胃。” (Ginger peel: acrid-cool. Disperses floating oedema, abdominal distension, and stuffiness; harmonises the Spleen-Stomach.)
• The theoretical basis for ginger peel’s distinct function: “姜肉性温，姜皮性凉。姜肉主发散，姜皮主行水。” (Ginger flesh nature is warm; ginger peel nature is cool. Ginger flesh governs dispersing outward; ginger peel governs moving water.)