Yu Ping Feng San

Yu Ping Feng San (Yù Píng Fēng Sǎn) is a classical Chinese herbal formula first recorded in the Dan Xi Xin Fa (Teachings of Zhu Danxi) by Zhu Danxi (c. 1481, Yuan dynasty). The formula name literally translates to "Jade Screen Powder" — Yu means jade, Ping means screen or barrier, and Feng refers to Wind, the primary external pathogenic factor in TCM theory. The name poetically describes the formula's function: like a precious jade screen placed before a person, it creates a protective barrier that shields the body from external pathogenic Wind.

In the TCM classification system, this formula belongs to the category of formulas that tonify Qi and secure the exterior (yi qi gu biao). Its primary therapeutic strategy addresses a specific pathological pattern: when Lung and Spleen Qi are deficient, the defensive Qi (Wei Qi) that circulates at the body's surface becomes unstable and fails to secure the exterior. This allows pathogenic Wind to penetrate easily, leading to spontaneous sweating (as the pores fail to close properly), aversion to wind, and recurrent upper respiratory infections.

Within TCM education, Yu Ping Feng San is considered one of the most important formulas for securing the exterior and is a paradigmatic example of Zhu Danxi's approach to preventive medicine. The formula is notable for its elegant simplicity: with only three herbs, it accomplishes the sophisticated therapeutic goal of simultaneously tonifying the interior (to strengthen the body's defensive capacity) and securing the exterior (to prevent pathogenic invasion). This economy of means reflects the Yuan dynasty medical tradition's emphasis on clear pattern differentiation and targeted treatment.

In modern TCM clinical discussion, the formula is frequently mentioned in the context of recurrent respiratory tract infections (especially in children and elderly individuals), allergic rhinitis, spontaneous sweating, chronic fatigue with susceptibility to colds, and certain dermatological conditions associated with unstable exterior defense. These correspondences between TCM patterns and modern biomedical conditions are conceptual analogies, not equivalences.

The formula appears in the Dan Xi Xin Fa (Teachings of Zhu Danxi), a foundational text of the Yuan dynasty compiled by Zhu Danxi and his disciples around 1481. Zhu Danxi (1281–1358), also known as Zhu Zhenheng, was one of the four great physicians of the Jin-Yuan period and is particularly famous for his theory that yang is often excessive while yin is often insufficient, which emphasized the importance of nourishing Yin. However, Yu Ping Feng San demonstrates his equally sophisticated understanding of Qi-tonifying and exterior-securing strategies.

The original text describes the formula's indication for spontaneous sweating and aversion to wind due to exterior deficiency. The classical presentation includes sweating with slight exertion or exposure to wind, recurrent colds, fatigue, a pale tongue with thin white coating, and a floating, deficient pulse. The formula is specifically indicated when the body's defensive barrier is weakened by Qi deficiency, allowing external pathogens to repeatedly invade.

The name "Jade Screen" carries rich symbolic meaning in Chinese culture. Jade was considered the most precious of stones, associated with purity, durability, and protective power. A jade screen was a luxury item placed before important individuals to shield them from drafts and unwanted influences. By naming the formula after this object, Zhu Danxi conveyed both the formula's protective function and its precious therapeutic value. The formula has remained in continuous use for over 600 years and is one of the most widely studied TCM formulas in modern research.

The following are traditional TCM pattern descriptions and are not modern medical diagnoses or treatment recommendations.

In the classical TCM framework, Yu Ping Feng San addresses the pattern of Qi deficiency with unstable exterior defense. The primary traditional indications include:

• Spontaneous sweating due to exterior deficiency — Sweating that occurs without exertion or heat exposure, particularly on the forehead and upper body. The sweating worsens with slight physical activity or exposure to wind, and the patient typically feels chilly afterwards. This reflects the failure of Wei Qi to secure the pores (cou li).
• Aversion to wind and recurrent colds — A chronic tendency to catch colds, often with the patient reporting that they "catch every cold that goes around." The pattern is characterized by aversion to drafts and wind, and the recurrent infections tend to be mild but frequent rather than severe.
• Fatigue and weakness with exterior vulnerability — Generalized fatigue, weakness, and lack of energy, often accompanied by shortness of breath and a weak voice. These symptoms reflect the underlying Lung and Spleen Qi deficiency that permits the exterior to become unstable.
• Allergic rhinitis with Qi deficiency pattern — In modern TCM clinical discussion, the formula is frequently used for allergic rhinitis when the patient presents with Qi deficiency signs (fatigue, pale tongue, weak pulse) alongside sneezing, clear nasal discharge, and nasal itching. The theoretical rationale is that deficient Wei Qi fails to protect the nasal mucosa from allergen exposure.
• Tongue and pulse signs — A pale tongue body with thin white coating, reflecting Qi deficiency. The pulse is typically floating and deficient (fu xu mai) — floating (indicating the exterior) and deficient (indicating Qi deficiency).

Modern TCM clinical discussion has expanded the formula's theoretical applications to include chronic urticaria (when associated with Qi deficiency and Wind invasion), chronic bronchitis with frequent exacerbations, and as a preventive formula during seasonal changes for individuals with weakened immune function. These expanded applications remain within the TCM pattern framework and have varying levels of supporting evidence.

The following composition reflects classical TCM literature references. Specific dosages are for educational reference only and are not dosage recommendations.

Formula Explanation (Fang Jie)

The architectural logic of Yu Ping Feng San can be understood through three functional herbs operating in concert:

• Huang Qi — Chief Herb: Tonifies Qi and Secures the Exterior. Huang Qi (Astragalus Root) is the principal herb and the foundation of the formula's therapeutic strategy. In TCM pharmacology, it is described as sweet and slightly warm, entering the Spleen and Lung channels. It strongly tonifies Spleen and Lung Qi, raises Yang Qi, and secures the exterior to stop sweating. Its role as chief addresses the root cause of the pattern — Qi deficiency that permits the exterior to become unstable. Modern pharmacological studies have identified astragalosides and polysaccharides as primary bioactive compounds with immunomodulatory, anti-inflammatory, and antioxidant properties.
• Fang Feng — Deputy Herb: Dispels Wind and Assists in Securing the Exterior. Fang Feng (Saposhnikovia Root) serves as deputy with a subtle but crucial function. In TCM pharmacology, it is acrid, sweet, and slightly warm, entering the Bladder, Liver, and Spleen channels. It dispels Wind, releases the exterior, and overcomes dampness. In this formula, its role is not to strongly release the exterior (as it would in an exterior-releasing formula for acute colds), but rather to gently assist Huang Qi in securing the exterior against pathogenic Wind invasion. The combination of Huang Qi and Fang Feng exemplifies a sophisticated TCM principle: securing the exterior while dispelling Wind, where the body's defensive barrier is strengthened while residual or lingering Wind is gently expelled.
• Bai Zhu — Adjuvant Herb: Tonifies Spleen Qi and Dries Dampness. Bai Zhu (Atractylodes Rhizome) tonifies Spleen Qi, dries Dampness, and strengthens the Middle Jiao to support Qi production. In TCM theory, the Spleen is the source of Qi and Blood production; by strengthening the Spleen, Bai Zhu supports the generation of Qi that Huang Qi then directs to secure the exterior. This creates an elegant internal logic: Bai Zhu strengthens the source (Spleen), Huang Qi directs the Qi to the exterior (Lung and surface), and Fang Feng ensures that the exterior remains clear of pathogenic Wind. Without Bai Zhu, the formula would lack the foundational support for sustainable Qi production.

The overall therapeutic strategy can be summarized as tonifying Qi to secure the exterior and stop sweating (yi qi gu biao zhi han). This elegant three-herb composition exemplifies Zhu Danxi's sophisticated clinical reasoning: the formula simultaneously addresses the root (Qi deficiency through tonification) and the branch (unstable exterior and sweating through securing and astringing), accomplishing multiple therapeutic goals with remarkable economy.

Modern research on Yu Ping Feng San has accumulated over several decades, with studies spanning preclinical pharmacology, clinical trials, and meta-analyses. The formula is widely used in China as both a decoction and a proprietary granule preparation (Yupingfeng granules). While the evidence base is growing, it remains largely preliminary. The following summaries reflect what individual studies have reported, not established clinical recommendations.

Level 1: Exact Formula Research

Studies investigating the complete classical formula as a whole preparation.

Recurrent Respiratory Tract Infections in Children

Yu Ping Feng San has been extensively studied for recurrent respiratory tract infections (RRTIs) in children, particularly as an adjuvant therapy. A 2016 meta-analysis by Song T et al. (PMID: 27145435) published in Phytotherapy Research analyzed randomized controlled trials of Yu Ping Feng Formula as adjuvant treatment for RRTIs in children. The meta-analysis reported that adjuvant treatment improved total clinical effective rate and decreased the frequency of recurrent infections. A 2022 systematic review and meta-analysis by Zhang L et al. (PMID: 36619520) published in Frontiers in Pediatrics similarly evaluated Yupingfeng granules as adjuvant treatment for RRTIs in children and found potential benefits in reducing recurrence rates and improving immune function markers. However, both meta-analyses noted limitations including small sample sizes, methodological heterogeneity, and variable quality among included studies.

Allergic Rhinitis

Several studies have investigated Yu Ping Feng San for allergic rhinitis. A 2025 randomized, double-blind, placebo-controlled trial by Lin ZX et al. (PMID: 40420199) published in Chinese Medicine evaluated a modified Yu-Ping-Feng powder against allergic rhinitis. The study reported improvements in Total Nasal Symptom Score (TNSS) and Rhinoconjunctivitis Quality of Life Questionnaire scores in the treatment group compared to placebo. A 2026 clinical trial by Hu Y et al. (PMID: 40967489) published in Journal of Ethnopharmacology investigated Yu-Ping-Feng nasal drops and reported relief of allergic rhinitis symptoms via modulation of the TRPV1/Ca(2+)/NFAT pathway. A 2025 systematic review and meta-analysis by Li Z et al. (PMID: 41229058) published in Allergologia et Immunopathologia evaluated Yupingfeng powder combined with acupuncture for allergic rhinitis and reported potential synergistic benefits. These studies suggest biological plausibility, but larger, higher-quality trials are needed.

Chronic Bronchitis and Anti-Inflammatory Effects

A 2013 study by Song J et al. (PMID: 23504545) published in Chinese Journal of Integrative Medicine investigated the anti-inflammatory and immunoregulatory effects of Yupingfeng powder on a rat chronic bronchitis model. The study reported that the formula demonstrated anti-inflammatory activity and immunomodulatory effects, including reductions in inflammatory cytokines and improvements in immune cell function. While these preclinical findings provide mechanistic hypotheses, they cannot be directly extrapolated to clinical effectiveness in humans.

Influenza and System Pharmacology

A 2025 study by Chen R et al. (PMID: 39121925) published in Journal of Ethnopharmacology explored the action mechanism and effective components of Yupingfeng powder on influenza using computational system pharmacology and metabolomics. The study identified potential molecular targets and pathways through which the formula might exert effects on influenza-related processes. While network pharmacology provides hypotheses for further investigation, these computational findings cannot be directly extrapolated to clinical effectiveness.

Prevention of Hospital-Acquired Pneumonia

A 2010 randomized controlled trial by Yan L et al. (PMID: 20082754) published in Journal of Chinese Integrative Medicine investigated the prevention of hospital-acquired pneumonia with Yupingfeng Powder in patients with acute cerebral vascular diseases. The study reported that the formula showed preventive effects worth further investigation. However, this was a small study with limited generalizability.

Level 2: Variant Research

Studies investigating modified versions of this formula or closely related combinations.

Combined Therapy with Conventional Treatments

Several studies have investigated modified Yu Ping Feng San combined with conventional treatments. A 2019 meta-analysis by Zhang LD et al. (PMID: 31872622) published in Zhongguo Zhong Yao Za Zhi evaluated Yupingfeng Granules combined with Western medicine for recurrent respiratory tract infection and reported that the combination showed better total effective rate than Western medicine alone. A 2018 meta-analysis by Shi X et al. (PMID: 30024564) published in Medicine (Baltimore) investigated Yupingfeng formula as adjuvant treatment for primary nephrotic syndrome in children. While these studies suggest potential adjuvant benefits, the evidence quality remains low due to methodological limitations.

Level 3: Family Research

Studies investigating formulas in the same therapeutic family (Qi-tonifying and exterior-securing category).

Related Qi-Tonifying Formulas

Research on formulas from the same therapeutic family provides complementary context. Bu Zhong Yi Qi Tang, which shares the strategy of Qi tonification with Huang Qi as chief, has been studied for chronic fatigue, organ prolapse, and immune modulation. Si Jun Zi Tang, the foundational Spleen Qi-tonifying formula, has been investigated for digestive dysfunction and immune support. A 2026 review by Gao S et al. (PMID: 42182585) published in Drug Design, Development and Therapy systematically summarized advances in Yu Ping Feng San research, including multi-target mechanisms and clinical evidence across various diseases. While these related formulas differ in composition, the shared therapeutic principle of Qi tonification suggests biological plausibility, but the evidence remains preliminary.

Level 4: Ingredient-Related Research

Studies investigating individual herbs or compounds from this formula — findings may not reflect the complete formula's effects.

Huang Qi (Astragalus membranaceus)

Huang Qi contains astragalosides, polysaccharides, and flavonoids as primary bioactive compounds. Astragaloside IV has demonstrated immunomodulatory, anti-inflammatory, antioxidant, and cardioprotective properties in preclinical studies. Astragalus polysaccharides have been studied for their effects on immune cell proliferation, cytokine production, and gut microbiota modulation. Clinical studies of Astragalus extracts have investigated applications in chronic fatigue, immune support, and cardiovascular health. However, individual herb findings cannot be directly extrapolated to the clinical effectiveness of the complete formula.

Fang Feng (Saposhnikovia divaricata) and Bai Zhu (Atractylodes macrocephala)

Fang Feng contains chromones, coumarins, and polyacetylenes as primary bioactive compounds. These compounds have demonstrated anti-inflammatory, analgesic, and immunomodulatory effects in preclinical studies. Bai Zhu contains atractylodin, atractylon, and sesquiterpenoid lactones, which have demonstrated anti-inflammatory, gastrointestinal regulatory, and immunomodulatory effects. Atractylodes compounds have been studied for their effects on digestive function, fluid metabolism, and immune regulation. These individual herb findings provide pharmacological context but cannot be directly extrapolated to the complete formula's effects.

Pharmacological Mechanisms (Preclinical Summary)

Collectively, the bioactive compounds identified across the herbs in Yu Ping Feng San have demonstrated the following mechanisms in preclinical studies: immunomodulation via regulation of T-cell subsets, cytokine production, and macrophage activity (astragalus polysaccharides); anti-inflammatory activity via NF-kappa B and COX-2 inhibition (chromones, sesquiterpenes); antioxidant effects via scavenging of free radicals (flavonoids, polysaccharides); barrier function enhancement via tight junction protein regulation; and antiviral activity against respiratory pathogens (various constituents). However, these isolated compound findings cannot be directly extrapolated to the clinical effectiveness of the complete formula in humans.

Overall Evidence Limitations

Key limitations of the existing evidence base include: most clinical studies were conducted in single centers in China with small sample sizes; many studies were published in Chinese-language journals, limiting accessibility and peer review scrutiny; few studies used adequate placebo controls or blinding; many studies investigated the formula as adjuvant therapy rather than as a standalone treatment; heterogeneity in formula preparation, dosage, and duration across studies; long-term safety data are absent; and the gap between preclinical pharmacological findings and clinical evidence remains substantial. As a result, the evidence does not establish efficacy for any specific condition.