Wu Jia Pi (五加皮) — TCM Herb for Bi-Syndrome & Lower Limb Weakness

At a Glance

• Herb: Wu Jia Pi
• Chinese name: 五加皮 (Wǔ Jiā Pí)
• Latin name: Acanthopanacis Cortex
• Nature: Warm
• Taste: Acrid / Bitter
• Meridian: Liver / Kidney
• Category: Herbs that Expel Wind-Dampness
• Introduction: Wu Jia Pi (Cortex Acanthopanacis) is the root bark of Acanthopanax gracilistylus (Nan Wu Jia), preferred in southern China for its safety profile. Important distinction: Xiang Wu Jia Pi (Cortex Periplocae) from Periploca sepium — a northern substitute — contains cardiac glycosides and must not be used interchangeably or in high doses. First recorded in the Shen Nong Ben Cao Jing, this pungent, bitter, and warm herb both expels Wind-Damp and tonifies the Liver and Kidney, making it uniquely suited for both Bi-syndrome and developmental weakness in children. Modern research on acanthosides from the Acanthopanax genus demonstrates adaptogenic, immunomodulatory, and anti-fatigue effects, explaining its use in endurance medicine.

Action

• Dispels Wind-Damp and relieves Bi-syndrome pain
• Strengthens the sinews, bones, and lower limbs
• Tonifies the Liver and Kidney
• Promotes urination and reduces edema

Clinical Application

• Wind-Cold-Damp Bi-syndrome with Liver-Kidney deficiency — lower back and knee pain, weakness, and fatigue
• Developmental delay in children — delayed walking, Five Softs (wu ruan) from insufficient Liver-Kidney essence
• Lower extremity weakness and difficulty walking in the elderly
• Edema from Qi deficiency with Wind-Damp accumulation

Precautions

• Dose: 5–10 g in decoction
• Always clarify which Wu Jia Pi is being used — Nan Wu Jia Pi (Acanthopanax) is safe; Xiang Wu Jia Pi (Periploca) contains cardiac glycosides and must not be overused
• Contraindicated in Yin deficiency with internal Heat — warm and drying nature may aggravate
• Use cautiously in patients with cardiac arrhythmias, especially with Xiang Wu Jia Pi

Formula

• Wu Jia Pi San (五加皮散) — Wu Jia Pi + Niu Xi + Du Zhong + Xu Duan + Mu Gua, for lower back and knee Bi-syndrome with Liver-Kidney deficiency
• Wu Jia Pi Jiu (五加皮酒) — Wu Jia Pi macerated in rice wine, classical tonic wine for joint health and longevity
• Combined with Huang Qi and Fu Ling for edema with Qi deficiency
• Combined with Gui Ban and Long Gu for developmental weakness in children

Combinations

• Acanthopanax Bark (五加皮) + Achyranthes Root (牛膝) + Chinese Quince (木瓜) → expel wind-damp, strengthen sinews; lower limb weakness, beriberi, and edema
• Acanthopanax Bark (五加皮) + Eucommia Bark (杜仲) + Himalayan Teasel Root (续断) → tonify the Liver and Kidney, strengthen sinews and bones; lower back and knee weakness with wind-damp

Pharmacological Effects

• Adaptogenic
  • acanthosides — enhance stress resistance, similar to Siberian ginseng
• Anti-inflammatory; analgesic; immunomodulatory; anti-fatigue; cardioprotective; hepatoprotective; diuretic
  • promotes water metabolism
• Antioxidant; note: acanthopanax gracilistylus
  • 南五加皮) is preferred — Periploca sepium (北五加皮/香加皮) contains cardiac glycosides and is toxic
  • do not confuse

Classic Description

• Shen Nong Ben Cao Jing (《神农本草经》): ‘Governs heart and abdominal hernia pain, benefits qi, treats paralysis and inability to walk in children, and malignant sores with yin erosion.’
• Ben Cao Gang Mu (《本草纲目》): ‘Acanthopanax Bark treats wind-damp wilting and impediment and strengthens sinews and bones — its function is profoundly beneficial; taking it opens the diaphragm, removes hernia qi, moves impediment, brightens the eyes, descends qi, benefits qi and supplements deficiency; treats male impotence, damp scrotum, urinary dribbling, female genital itching, lower back and spine pain, and leg pain.’