Properties: Sweet, bitter, astringent, warm

Meridans Entered:
Primary: Kidney, Spleen, Lung, Pericardium
Extraordinary Vessels: Chong, Yin Qiao

1. Tonifies the Kidneys, strengthens Yang, stabilizes Jing and astringes urine
   Impotence, premature ejaculation, enuresis, urinary frequency, a cold and painful lower back and extremities
   Wheezing and shortness of breath due to Kidneys not grasping the Lung Qi
   Weakening of Ming Men Fire
2. Tonifies and warms Spleen and Kidney Yang to stop diarrhoea
   Diarrhoea with borborygmus and abdominal pain
   Cock-crow diarrhoea
   Most appropriate for those with both Spleen and Kidney Yang Deficiency
3. Warms the skin and regulates the blood (soaked in wine and applied topically)
   Cold-type psoriasis, vitiligo and eczema
   Hyperpigmentation
   Dry, dull or loose skin with fine lines or rough texture

Suggested Daily Dosage: 5-15g in decoction.

Cautions: Contraindicated in cases of Yin deficiency with effulgent Fire and constipation.

Due to the psoralen content which increases the response to UV light, patients should be advised to avoid excessive exposure to the sun or discontinue taking if traveling to a hot climate.

• Psoralen
  Furocoumarin that causes photosensitivity and has been used in conjunction with UV therapy for psoriasis and vitiligo to enhance the effect, but may also enhance risks of skin cancer and liver injury dye to raised enzymes.
• Angelicin
  Isomer of psoralen with similar photosensitising effects.
• Psoralidin
  Coumestan with in vitro evidence for anti-cancer activities and anti-depressant activity in mouse models but with poor water solubility.
• Bakuchiol
  Meroterpene with similar structure to reservatrol. It has reported to have anti-cancer activities in preclinical models and protect against bone loss in rat models.
• Corylifolinin
  A trans-chalcone with antibacterial and platelet aggregation inhibitory actions.

Notes:

The "bone fat" referred to in its name is the marrow. Li Shizhen wrote in the Bencao Gangmu: "Poguzhi belongs to fire, it can gather together the Shen by allowing the fire of the Ming Men to communicate smoothly without obstruction with the fire of the Pericardium. This results in the Primordial Yang being held firm and solid and keeps the bone marrow full and rich."

Its alternative name, Po Gu Zhi 破故紙 translates as "broken old paper" which raises further questions.

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Mazin Al-Khafaji also describes Bu Gu Zhi as "natures retinol" with "antioxidant with anti-inflammatory properties ... stimulating cell turnover (which in turn stimulates collagen), diminishing hyperpigmentation, moisturising skin, smoothing fine lines, refining skin texture, boosting radiance and enhancing skin firmness," (Al-Khafaji, 2023).