Ying as part of the Four Levels
The Ying Level is the third stage in the Four Levels diagnostic framework for warm febrile diseases (Wen Bing), representing a serious phase where pathogenic heat has penetrated deeply to affect the nutritive Qi and the Heart/Mind, characterized by fever worse at night, mental disturbances, and a crimson tongue.
Yíng Fēn
Ying Level (Nutritive Level)
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Overview
The Ying Level (营分, Yíng Fēn) represents the third and more serious stage in the Four Levels diagnostic system used in Traditional Chinese Medicine for analyzing warm febrile diseases (温病, Wēn Bìng). When a pathogen reaches this level, it has penetrated beyond the superficial Wei (defensive) and intermediate Qi levels into the nutritive layer of the body.
Think of the Ying Level as the body's inner circulation system being affected by heat. While the Wei and Qi levels deal with the body's outer defenses and functional energy, the Ying Level involves the nutritive substances that flow through the blood vessels and nourish the organs. When heat invades this level, it damages the body's deeper nourishing fluids (Yin) and disturbs the Heart and mind (Shen).
The primary organ systems affected at this level are the Heart and Pericardium. This explains why mental symptoms like restlessness, insomnia, and even delirium are hallmark features. The progression to the Ying Level signifies that the disease has become more dangerous and requires immediate, aggressive treatment to prevent further damage to the Blood level.
Historical Context
The Four Levels diagnostic framework, including the Ying Level, was systematized by the renowned Qing Dynasty physician Ye Tianshi (叶天士, 1667-1746) in his influential work 'Wen Re Lun' (温热论, Treatise on Warm Heat Diseases). This diagnostic method built upon and complemented the earlier Six Stages theory from Zhang Zhongjing's Shang Han Lun, specifically addressing warm-heat diseases rather than cold-damage conditions.
The system was further developed by subsequent Wen Bing school physicians including Wu Jutong (吴鞠通) in his 1798 work 'Wen Bing Tiao Bian' (温病条辨, Systematic Differentiation of Warm Diseases). Ye Tianshi famously stated that 'after Wei comes Qi, after Ying comes Blood' (卫之后方言气，营之后方言血), establishing the sequential progression principle. The Four Levels approach emerged during epidemics of infectious febrile diseases in China, providing physicians with a framework to track disease severity and guide treatment as illness progressed through the body.
Comparison
Wei Level
卫分Depth: Most superficial (skin/exterior)
Fever pattern: Fever with chills, mild
Thirst: Minimal or absent
Mental state: Normal
Tongue: Slightly red tip, thin white coat
Treatment: Release the exterior, expel Wind-Heat
Qi Level
气分Depth: Interior but functional (Lung, Stomach, Intestines)
Fever pattern: High fever, no chills, constant
Thirst: Intense thirst, wants cold drinks
Mental state: Irritable but conscious
Tongue: Red with thick yellow coat
Treatment: Clear Qi-level heat (e.g., Bai Hu Tang)
Ying Level
营分Depth: Deep interior (nutritive Qi, Heart)
Fever pattern: Fever worse at night
Thirst: Reduced, mouth dry but not very thirsty
Mental state: Restless, insomnia, possible delirium
Tongue: Crimson red, thin or no coat
Treatment: Clear Ying heat, nourish Yin (e.g., Qing Ying Tang)
Blood (Xue) Level
血分Depth: Deepest level (blood, Liver, Kidneys)
Fever pattern: Persistent high fever or low fever
Thirst: Variable
Mental state: Severe delirium, convulsions, coma possible
Tongue: Deep crimson or purple, dry
Treatment: Cool blood, stop bleeding (e.g., Xi Jiao Di Huang Tang)
Deep Heat Invasion
热入营分At the Ying Level, pathogenic heat has moved past the body's outer defensive and functional layers into the deeper nutritive level. This represents a significant worsening of the disease—the pathogen is no longer at the surface but has penetrated to affect the body's nourishing substances. The heat damages the Yin (cooling, nourishing fluids) and disrupts normal circulation.
Heart and Mind Disturbance
心神被扰Because the Ying (nutritive Qi) flows through the blood vessels and connects intimately with the Heart, heat at this level directly disturbs the Shen (spirit/consciousness). This produces characteristic mental symptoms: restlessness, insomnia, confused thinking, and in severe cases, delirium or unconsciousness. The Heart 'houses the Shen,' so when Ying-level heat affects the Heart, mental clarity is compromised.
Fever Pattern: Worse at Night
身热夜甚A key diagnostic marker of Ying Level pathology is fever that intensifies at night. This occurs because Yin energy naturally predominates during nighttime hours, and when Yin is damaged by internal heat, the conflict between pathogenic heat and depleted Yin becomes most pronounced after dark. This pattern helps distinguish Ying Level from Qi Level, where fever tends to be high and constant regardless of time.
Crimson Tongue
舌质红绛The tongue becomes deep red or crimson (绛, jiàng) at the Ying Level, often with a reduced or absent coating. This color change reflects heat in the blood vessels and damage to the body's fluids. A crimson tongue is considered a critical diagnostic sign that heat has penetrated to the Ying or Blood level and requires immediate cooling treatment.
Emerging Skin Rashes
斑疹隐现Faint rashes or maculae (斑疹) may begin to appear on the skin at the Ying Level, though they are not yet fully expressed. These represent heat 'steaming outward' from the blood vessels. When rashes become prominent, dark, or purple, this typically indicates progression to the Blood Level. The appearance of rashes helps track how deeply heat has invaded.
Reversal Transmission
逆传心包A dangerous pattern called 'reversal transmission to the Pericardium' (逆传心包) can occur when heat bypasses the normal sequential progression and jumps directly from the Wei Level to the Ying Level. This happens in cases of severe pathogenic virulence, constitutional weakness of the Heart, or improper treatment. Reversal transmission is considered an emergency requiring immediate intervention.
Practical Application
Recognizing Ying Level Patterns: Practitioners identify Ying Level invasion through a characteristic cluster of signs: fever that worsens at night, restlessness and insomnia, possible mental confusion or delirium, reduced thirst (unlike Qi Level where thirst is intense), faint skin rashes, a deep red or crimson tongue with little coating, and a thin, rapid pulse. The patient may feel hot to the touch, especially in the evening.
Treatment Strategy: The primary treatment principle is 'Clear Ying Heat and Protect Yin' (清营解毒，护阴). This means using cooling herbs that target the nutritive level while simultaneously nourishing the depleted body fluids. Unlike Qi Level treatment which focuses on strong heat-clearing, Ying Level treatment must balance cooling with protection of the body's nourishing substances. The classic formula Qing Ying Tang (清营汤) embodies this approach. In acupuncture, points that clear Heart heat and calm the spirit are emphasized, such as HT-7 (Shenmen), PC-6 (Neiguan), and PC-8 (Laogong).
Preventing Progression: A critical clinical goal is preventing heat from advancing to the Blood Level, where bleeding and more severe complications occur. Practitioners aim to 'vent' the heat outward from Ying back toward Qi level—essentially pushing the pathogen from deeper to more superficial layers where it can be expelled. This requires careful formula construction and timely intervention.
Clinical Relevance
Modern Clinical Applications: The Ying Level framework remains relevant in managing severe febrile illnesses. In modern clinical practice, Ying Level patterns may be seen in conditions such as encephalitis, meningitis, severe sepsis, typhoid fever, and other serious infectious diseases where high fever is accompanied by mental status changes. The framework guides practitioners in assessing disease severity and tailoring treatment accordingly.
Key Diagnostic Indicators: Clinicians look for the combination of: (1) fever worse at night rather than constant high fever, (2) mental symptoms ranging from mild restlessness to delirium, (3) reduced thirst despite feeling hot, (4) crimson tongue with thin or absent coating, and (5) thin, rapid pulse. When these signs cluster together, Ying Level treatment protocols are indicated.
Integration with Western Medicine: In integrative settings, recognizing Ying Level patterns can complement conventional treatment by identifying patients at higher risk for neurological complications and guiding supportive therapies. The Chinese medicine research has shown that Ying Level treatment methods may have anti-inflammatory, neuroprotective, and fever-reducing effects relevant to managing severe infections.
Common Misconceptions
'The Four Levels always progress sequentially': While the typical pattern moves from Wei → Qi → Ying → Blood, disease can skip levels or present at multiple levels simultaneously. Heat may transmit directly to the Ying Level (reversal transmission) or a patient may show combined Qi-Ying patterns. The framework describes tendencies, not rigid rules.
'Ying Level is the same as Blood Level': Though closely related, these are distinct stages. The Ying Level primarily affects nutritive Qi and causes mental disturbances, while the Blood Level involves frank bleeding, severe hemorrhagic rashes, and more profound Yin damage. Treatments differ accordingly—Ying Level emphasizes cooling and protecting fluids, while Blood Level requires stronger cooling of blood and stopping bleeding.
'Any fever with confusion indicates Ying Level': Mental symptoms alone don't confirm Ying Level. The diagnosis requires the full pattern including the nocturnal fever pattern, tongue changes, and pulse characteristics. High Qi Level fever can also cause some mental agitation, but the fever pattern and tongue presentation differ.
Classical Sources
Wen Re Lun (温热论)
Opening passage温邪上受，首先犯肺，逆传心包。肺主气属卫，心主血属营
Warm pathogen is received from above, first attacking the Lungs, with possible reversal transmission to the Pericardium. The Lung governs Qi and pertains to Wei; the Heart governs Blood and pertains to Ying.
Wen Re Lun (温热论)
Transmission principles卫之后方言气，营之后方言血
After Wei comes Qi, after Ying comes Blood.
Wen Bing Tiao Bian (温病条辨)
Upper Jiao chapter热入营分，用清营汤
When heat enters the Ying level, use Qing Ying Tang (Clear the Nutritive Level Decoction).
Modern References
Warm Disease Theory and Clinical Application
Comprehensive modern textbook on Wen Bing theory with detailed discussion of Four Levels diagnosis and treatment
Chinese Herbal Medicine: Formulas and Strategies
Standard English-language reference covering formulas for Ying and Blood level heat patterns
Diagnosis in Chinese Medicine: A Comprehensive Guide
Accessible introduction to Four Levels differentiation for Western practitioners