Among TCM dermatology formulas, Pi Pa Qing Fei Yin (Loquat Leaf Lung-Clearing Drink) — now standardised as Pi Pa Qing Fei granules, included in China’s Classical Ancient Formulas Catalogue (First Batch) and approved by the National Medical Products Administration in 2023 — remains one of the most clinically relevant formulas for acne and facial skin conditions. Recorded in Yi Zong Jin Jian · Wai Ke Xin Fa Yao Jue under the Qianlong Emperor, its indication was precise: “This pattern arises from Blood-Heat of the Lung channel. It erupts on the face and nose, forming small papules the size of millet seeds, red in colour and painful; when broken, white greasy fluid exudes; over time they form white scales. Internally administer Pi Pa Qing Fei Yin.” This description maps directly to the modern diagnosis of acne vulgaris (grade I–III), with the pathomechanism clearly identified as Lung channel Blood-Heat熏蒸 (fumigating) the face.

I. Historical Source and Formula Rationale

Pi Pa Qing Fei Yin is named after its chief herb: Pi Pa Ye (loquat leaf) is slightly cold and enters the Lung and Stomach channels, making it the primary herb for clearing Lung Heat and descending Lung Qi — Qing Fei (clearing the Lung) directly states the formula’s therapeutic action and its theoretical basis in TCM’s Lung governs skin and body hair principle. When Lung Heat is cleared, the Heat stops fumigating the skin, and the facial manifestations resolve from their root.

The formula’s distinctive design compared to other acne formulas: it does not rely on purely bitter-cold herbs that may damage the Spleen-Stomach. Instead, it includes Ren Shen (Ginseng) and Gan Cao to protect the Middle Jiao, making it clear without damaging, purge without depleting — suitable for the long-term treatment that chronic acne management often requires. This constitutional consideration sets it apart from single-mechanism heat-clearing approaches.

II. Six-Herb Composition and Formula Analysis

The formula contains six herbs: Mi Pi Pa Ye (honey-processed loquat leaf) · Sang Bai Pi (mulberry root bark) · Huang Lian (Coptis) · Huang Bai (Phellodendron) · Ren Shen (Ginseng) · Gan Cao (Licorice root).

Chief herb — Mi Pi Pa Ye (Honey-processed Loquat leaf): bitter, slightly cold; enters Lung, Stomach. Clears Lung Heat and moistens Dryness, descends Lung Qi and dissolves Phlegm, clears Stomach Heat. Why honey-processed? Raw loquat leaf has a stronger cold nature that risks damaging Spleen-Stomach with prolonged use; honey-processing moderates the cold nature while preserving the Lung-clearing and Stomach-clearing actions. Loquat leaf directly addresses both the Lung-channel source of the skin-fumigating Heat and the Stomach-channel dimension contributing to facial oiliness and oral dryness.

Deputy herb — Sang Bai Pi (Mulberry root bark): sweet, cold; enters Lung. Clears Lung Heat and purges Lung Fire, promotes urination. Amplifies Pi Pa Ye’s Lung-channel Heat clearance while adding a diuretic dimension — assisting Heat-pathogen expulsion through urination, reducing internal Damp-Heat that manifests as skin oiliness and pore blockage.

Assistant herbs — Huang Lian and Huang Bai: both are bitter-cold Damp-Heat-clearing herbs. Their pairing doubles Heat-toxin clearing and Damp-drying potency:

• Huang Lian: enters Heart, Liver, Stomach, Large Intestine; clears Heat, dries Damp, purges Fire and detoxifies. Specialises in middle-upper Jiao Damp-Heat, especially Stomach Fire and Heart Fire — addressing the gastric-Fire component of the formula’s target pattern: pus-filled papules, oral malodour, constipation, restlessness.
• Huang Bai: enters Kidney, Bladder, Large Intestine; clears Heat, dries Damp, purges Fire and detoxifies, nourishes Yin and descends Fire. Specialises in lower-Jiao Damp-Heat, but here assists Huang Lian in clearing Stomach Fire and addresses the Blood-Heat Stasis component of nodular and cystic acne. Together the two Huang herbs tackle both the active Heat-toxin (acute inflammatory acne) and the underlying Blood-Heat-Stasis (slow-resolving post-inflammatory lesions).

Assistant herb — Ren Shen (Ginseng): sweet-slightly bitter, slightly warm; enters Spleen, Lung, Heart. Greatly supplements original Qi, strengthens Spleen-Stomach, generates fluids and calms Spirit. Ren Shen’s role in this formula is critical and distinctive: the formula’s many cold-natured herbs (Pi Pa Ye, Sang Bai Pi, Huang Lian, Huang Bai) risk damaging Spleen-Stomach Yang with prolonged use. Ren Shen warm-supplements the Middle Jiao, simultaneously: (1) protecting Spleen-Stomach from cold damage; (2) supplementing the Qi depleted by the Heat pathogen; (3) generating fluids to counteract Heat-consuming Yin fluids. This makes Pi Pa Qing Fei Yin fundamentally different from purely bitter-cold acne formulas — it is suitable for constitutionally weaker patients and for sustained treatment.

Envoy herb — Gan Cao: sweet, neutral; clears Heat and detoxifies, harmonises all herbs. Assists Huang Lian and Huang Bai in clearing Heat-toxin; moderates the formula’s cold tendency with sweetness; protects Spleen-Stomach alongside Ren Shen. The peacemaker of the formula: prevents the cold herbs from over-suppressing Yang Qi.

Three-layer formula logic (Clear – Purge – Protect):
① Clear (Pi Pa Ye + Sang Bai Pi): directly clear Lung channel Heat from the source, resolving the “Lung Heat fumigating the face” mechanism
② Purge (Huang Lian + Huang Bai): clear Stomach Fire and Damp-Heat, address Blood-Heat-Stasis driving the inflammatory and nodular acne components; eliminate Heat through urination and bowel
③ Protect (Ren Shen + Gan Cao): supplement Qi and protect Spleen-Stomach, ensuring sustained treatment does not deplete righteous Qi or damage digestion

III. Core Pathomechanism: Lung-Stomach Heat with Blood-Heat Stasis

Three-stage pathological cascade:
① Lung Heat: generated by late nights, overwork, emotional stagnation transforming to Fire, or external Heat invasion → Heat ascends through the Lung channel to the face → red papules, facial dryness, dry throat, dry cough
② Stomach Fire: generated by spicy-oily-sweet diet, alcohol, excess heat-natured foods → Stomach Fire ascends to the face → facial oiliness, pus-filled papules, oral malodour, constipation
③ Blood-Heat Stasis: Lung and Stomach Heat combined, sustained over time, scorches the Blood vessels → Blood-Heat causing rebellious Blood flow → red swollen painful nodular acne, post-inflammatory erythema resistant to resolution

Core identification criteria for Pi Pa Qing Fei Yin pattern: facial red papules and/or pus-filled papules; facial oiliness; red tongue with thin yellow or yellow-greasy coating; floating-rapid or slippery-rapid pulse; accompanied by: oral dryness and bitterness, constipation, dark yellow urine, irritability; triggered or worsened by: late nights, spicy food, emotional stress.

IV. Clinical Applications and Modifications

1. Primary indication: Lung-Stomach Heat type acne (grades I–III)
Face, forehead, and perioral/nasal red papules, blackhead comedones, and/or pus-filled papules; oily skin; red swelling and tenderness; red tongue, yellow coating; floating-rapid pulse. Triggered by late nights, dietary excess, and emotional stress.

2. Rosacea (Lung-Stomach Heat type): nasal and perinasal facial redness, papules, pus-filled papules, and telangiectasia; dry mouth, constipation, restlessness — Lung-Stomach Heat with Blood-Heat Stasis pattern.

3. Seborrhoeic dermatitis (Damp-Heat type): facial and scalp oiliness, erythema, itching, and scaling; oral dryness and bitterness, constipation — Lung-Stomach Heat with Damp-Heat accumulation pattern.

4. Lung-Heat cough: cough with yellow thick phlegm, throat pain, mouth dryness, chest tightness — Pi Pa Ye and Sang Bai Pi as the core respiratory herbs address this as a secondary application.

5. Stomach-Fire oral ulcers: red painful oral and tongue ulcers, oral malodour, constipation — Huang Lian as the primary Stomach-Fire clearing herb addresses this pattern.

Common clinical modifications:

• Many pus-filled papules, marked swelling: add Jin Yin Hua 12g, Lian Qiao 9g, Pu Gong Ying 15g — amplify Heat-toxin clearing and abscess dispersion
• Severe facial oiliness: add Yi Yi Ren 20g, Ze Xie 12g, Yin Chen 9g — strengthen Damp-Heat clearing and sebum reduction
• Severe constipation: add Da Huang 6g (add last), Mang Xiao 6g (dissolve into strained liquid) — purge Heat downward from the root
• Prominent oral dryness: add Tian Hua Fen 12g, Mai Dong 12g, Sheng Di 12g — nourish Yin and generate fluids
• Nodular acne, persistent post-inflammatory erythema: add Dan Shen 15g, Mu Dan Pi 9g, Chi Shao 10g — cool Blood, activate Blood, and disperse Stasis to resolve pigmentation
• Spleen-Stomach weakness (loose stool, poor digestion): reduce Huang Lian and Huang Bai; add Bai Zhu 12g, Fu Ling 15g — prevent cold herb Spleen damage

V. Usage, Dosage, and Safety

Patent form: Hai Tian Pi Pa Qing Fei granules — warm water reconstitution; no decoction required. Decoction form also used in clinical settings for modified compositions.

Course: mild-moderate acne typically responds within 2–4 weeks of consistent use. For sustained improvement and prevention of relapse, 1–3 months of continued use may be recommended. Do not discontinue immediately on improvement of acute lesions — the underlying Lung-Stomach Heat constitution requires sustained treatment to prevent recurrence.

Contraindications:

• Pregnant and breastfeeding women: Huang Lian and Huang Bai are strongly bitter-cold and may affect foetal development; practitioner supervision required
• Spleen-Stomach Cold deficiency (cold aversion, loose stool, cold abdomen, pale tongue, white coating): the formula’s cold-heavy composition will worsen Cold symptoms significantly; if treatment is needed, substantially reduce Huang Lian and Huang Bai doses with warm-protective additions
• Allergy to any component: contraindicated
• Yin-deficiency without Damp-Heat: the formula’s drying herbs (Huang Lian, Huang Bai) will worsen Yin depletion

Pattern specificity: this formula is designed exclusively for Lung-Stomach Heat-driven acne. It will not help — and may harm — acne arising from: Qi stagnation and Blood Stasis without significant Heat (dark nodular acne, pale tongue, wiry pulse); Phlegm-Damp accumulation (cystic acne with pale tongue, greasy coating, no redness); or Spleen-Stomach deficiency (pale papules, cold constitution). Pattern identification is non-negotiable.

Lifestyle co-treatment (without which formula effects are limited): reduce or eliminate spicy, oily, sweet-greasy, and fried foods; reduce alcohol; maintain regular sleep schedule and avoid late nights; manage stress (emotional Fire directly worsens Lung-Heat); gentle facial cleansing without stripping the skin barrier; avoid over-applying comedogenic cosmetics; adequate water intake.