Xue (Blood)
Blood (Xue) is a dense, red, nourishing fluid that circulates within the vessels to moisten and nourish all tissues of the body. It is both a material substance and an energetic carrier that supports physical health, mental clarity, and consciousness.
Xuè
Blood
Educational content · Consult qualified TCM practitioners for diagnosis and treatment
Source & Origin
Blood in TCM originates from two primary sources: Post-Heaven (acquired) sources derived from food and drink, and Pre-Heaven (inherited) sources connected to Kidney Essence (Jing).
The main source of Blood is the Spleen and Stomach, which transform food and drink into refined nutritive substances called "water and grain essence" (Gu Qi). This essence is sent upward to the Lungs and Heart, where it undergoes a final transformation—"changing to red"—to become Blood. This process requires the catalytic action of Heart Fire (Yang) and the participation of Lung Qi.
The secondary source comes from Kidney Essence, which produces Marrow. Marrow in turn contributes to Blood formation, establishing the relationship often expressed as "Essence and Blood share the same source." This explains why chronic Blood deficiency often involves the Kidneys, and why nourishing the Kidneys is important for building Blood long-term.
Formation Process
The formation of Blood is a complex process involving multiple organs working in harmony. The classical text Ling Shu states: "The Middle Burner receives Qi and extracts the juice, transforms and changes it to red—this is called Blood."
The process begins when the Spleen and Stomach digest food and extract nutritive essence (Gu Qi). This essence, combined with fluids (Jin Ye), forms the raw material for Blood. The Spleen then sends this refined substance upward to the Lungs, where it combines with fresh Qi from respiration and undergoes gas exchange. From the Lungs, this mixture travels to the Heart, where Heart Fire transforms it into red Blood through a process described as "transforming and changing to red."
Additionally, Kidney Essence produces Marrow, which generates bone marrow that contributes to Blood formation—a concept remarkably similar to modern understanding of hematopoiesis. The Liver also plays a role by storing Blood and ensuring its smooth distribution, while Kidney Yang provides the warming energy needed for all transformative processes.
Location in Body
Blood circulates continuously within the vessels (Mài), which form a closed system throughout the body. The Heart governs the vessels, and Blood flows through them to reach every organ, tissue, and extremity. This circulation follows both the major meridian pathways and the smaller collateral vessels.
While circulating, Blood has special relationships with certain organs: the Heart governs its circulation, the Liver stores it when the body is at rest, the Spleen keeps it contained within the vessels, and the Lungs assist its distribution. The classical saying "When a person moves, Blood circulates to the channels; when at rest, Blood returns to the Liver" illustrates how Blood volume is dynamically regulated based on activity level.
Movement & Flow
Blood movement in TCM follows a cyclical pattern through the vessels, propelled primarily by the pushing action of Heart Qi and assisted by Lung Qi's dispersing function. The Liver's free-flowing (Shu Xie) function ensures smooth, unobstructed circulation.
Movement occurs in two directions: centrifugal (away from the heart through vessels to tissues) and centripetal (returning from tissues back toward the heart). Blood flows from larger vessels into progressively smaller branches (collaterals), eventually reaching the finest capillary-like vessels before returning. This circulation requires both a pushing force (provided by Heart, Lung, and Liver Qi) and a containing force (provided by Spleen Qi) to prevent leakage outside the vessels.
When Qi is strong and flowing smoothly, Blood circulation is healthy. When Qi becomes deficient or stagnant, Blood circulation suffers—either slowing down, becoming stuck (stasis), or escaping the vessels (hemorrhage).
In-Depth Study
In Traditional Chinese Medicine, Blood (Xuè, 血) is one of the fundamental vital substances that sustains life. Unlike the Western biomedical understanding of blood as simply a physical fluid carrying oxygen and nutrients, TCM views Blood as both a material substance and an energetic carrier of nourishment, emotion, and consciousness.
Blood is considered Yin in nature—dense, material, moistening, and nourishing. It flows continuously within the vessels (Mài, 脉), delivering nutrients to every organ, tissue, muscle, tendon, and sensory organ throughout the body. Blood works closely with Qi (vital energy): while Qi is the dynamic, invisible force that moves and protects, Blood is the substantial, visible fluid that nourishes and moistens.
A key TCM principle states that "Blood is the mother of Qi" and "Qi is the commander of Blood." This interdependent relationship means that healthy Blood provides the material foundation for Qi to function, while strong Qi ensures Blood circulates properly. When Blood is abundant and flowing freely, the body is well-nourished, the mind is calm, and the spirit (Shen) has a stable residence. When Blood becomes deficient or stagnant, various physical and emotional symptoms arise.
Historical Context
The concept of Blood (Xue) has been central to Chinese medicine since its earliest texts. The Huang Di Nei Jing (Yellow Emperor's Classic), compiled around 200 BCE, established foundational theories about Blood's formation, circulation, and pathology that remain relevant today. Remarkably, ancient Chinese physicians recognized that Blood originates from Marrow—a concept validated by modern hematology only in the 19th century.
Through subsequent dynasties, understanding of Blood deepened. Zhang Zhongjing's Shang Han Za Bing Lun (2nd century CE) developed treatment strategies for Blood disorders. The Ming dynasty physician Zhang Jiebin systematically organized Blood theory in his comprehensive medical works. The concept of Blood stasis (Yū Xue) received particular attention, with Wang Qingren's 19th-century text Yi Lin Gai Cuo developing numerous Blood-invigorating formulas still used today, including the famous Xue Fu Zhu Yu Tang.
Primary Functions
Nourishing the Body
濡养全身Blood's primary function is to nourish all tissues of the body. As it circulates through the vessels, Blood delivers essential nutrients to every organ, muscle, tendon, bone, skin, hair, and sensory organ. This complementary nourishment works alongside Nutritive Qi (Ying Qi), with Blood providing the substantial, material nutrients while Ying Qi provides the energetic nourishment. When Blood is abundant, the body is well-nourished, skin is healthy, muscles are strong, and eyes see clearly.
Moistening Tissues
滋润组织Blood has a moistening quality that prevents tissues from drying out. As a Yin substance, Blood keeps skin supple, joints lubricated, eyes moist, and hair glossy. This moistening function is especially important for organs and tissues that require constant hydration. When Blood is deficient, dryness manifests—dry skin, brittle nails, dry eyes, and parched hair.
Housing the Spirit (Shen)
藏神Blood provides the material foundation for the Spirit (Shen). The Shen—which encompasses consciousness, mental activity, memory, and emotional balance—resides in the Heart and requires Blood to anchor it. When Blood is sufficient, the mind is calm, sleep is peaceful, and emotions are balanced. When Blood is deficient, the Shen becomes unsettled, leading to anxiety, restlessness, poor memory, difficulty concentrating, and insomnia.
Supporting Vision
养目Blood nourishes the eyes and supports vision. The Liver opens to the eyes, and Liver Blood specifically nourishes visual function. Adequate Blood ensures clear, sharp vision and healthy, moist eyes. Blood deficiency often manifests as blurred vision, dry eyes, floaters, or night blindness—symptoms reflecting insufficient nourishment reaching the eyes.
Nourishing Tendons and Muscles
养筋Blood moistens and nourishes the tendons, ligaments, and muscles. The Liver governs tendons, and Liver Blood keeps them flexible and strong. When Blood adequately nourishes these tissues, movement is smooth and joints are flexible. Blood deficiency causes muscle weakness, cramps, numbness in limbs, stiff joints, and tremors.
Regulating Menstruation
主月经In women, Blood is fundamental to menstrual health. Regular, healthy menstruation depends on adequate Blood volume and proper circulation. The Liver stores Blood and releases it for menstruation, while the Spleen generates new Blood and holds it in the vessels. Blood deficiency causes scanty periods or amenorrhea; Blood stasis causes painful periods with dark clots.
Carrying Qi
载气Blood serves as the carrier or vehicle for Qi. The saying "Blood is the mother of Qi" reflects that Qi relies on Blood for transport throughout the body. Qi cannot reach tissues effectively without Blood carrying it there. This interdependence means that severe Blood loss also depletes Qi, and chronic Blood deficiency weakens overall vitality.
Relationship to Organs
Governs
The Heart governs Blood and blood vessels. Heart Qi provides the pumping force that circulates Blood throughout the body. The Heart also transforms essence into Blood through Heart Fire. Blood in turn houses the Shen (Spirit) which resides in the Heart.
Stores
The Liver stores Blood and regulates blood volume based on the body's needs. During rest, Blood returns to the Liver for storage; during activity, the Liver releases Blood to the muscles and tendons. The Liver's free-coursing function ensures smooth Blood circulation.
Produces
The Spleen is the primary source of Blood production as it transforms food essence into the raw materials for Blood. The Spleen also 'holds Blood in the vessels,' preventing hemorrhage through its containing function. Spleen deficiency commonly leads to Blood deficiency.
Transforms
The Lungs assist Blood formation by receiving refined essence from the Spleen and infusing it with fresh Qi from respiration. Through its function of 'governing vessels' and assisting Heart circulation, the Lungs help push Blood throughout the body.
Produces
The Kidneys store Essence (Jing) which produces Marrow. Marrow generates bone marrow that contributes to Blood formation, establishing the 'Essence and Blood share the same source' relationship. Kidney deficiency can lead to Blood deficiency over time.
Relationship to Other Substances
Qi and Blood are inseparable partners with a mutually dependent relationship described as "Qi is the commander of Blood, Blood is the mother of Qi." Qi performs three essential functions for Blood: Qi generates Blood (the transformation processes require Qi); Qi moves Blood (Heart Qi and Liver Qi propel circulation); and Qi holds Blood (Spleen Qi keeps Blood in the vessels). Conversely, Blood nourishes and carries Qi throughout the body. When either becomes deficient, the other suffers.
Essence (Jing) and Blood share the same source and mutually nourish each other. Kidney Essence produces Marrow, which contributes to Blood formation. Conversely, abundant Blood replenishes and supports Essence. This relationship is especially important in women's physiology, where Kidney Essence and Liver Blood together govern reproductive function and menstruation. Chronic Blood deficiency depletes Essence; Essence deficiency impairs Blood production.
Blood and Body Fluids originate from the same source (food essence) and mutually transform into each other. Fluids enter the vessels and become part of Blood; Blood fluids can exit to nourish tissues. This relationship has clinical significance: excessive sweating depletes Blood (hence the warning not to induce sweating in Blood-deficient patients); severe Blood loss causes fluid depletion and dryness. Both substances moisten the body, with Blood being the denser, redder form.
Blood provides the material residence for Shen (Spirit). The Shen—encompassing consciousness, mental clarity, memory, and emotional stability—anchors in the Heart where Blood is most concentrated. Sufficient Heart Blood keeps Shen calm and stable; Blood deficiency causes Shen to become unsettled, manifesting as anxiety, restlessness, poor concentration, dream-disturbed sleep, and emotional instability. Building Blood is essential for calming the spirit.
Nutritive Qi (Ying Qi) flows together with Blood inside the vessels, forming an inseparable pair. Ying Qi is the most refined, Yin aspect of Qi that provides direct nourishment to organs and tissues. It transforms into Blood and circulates with it. While Blood provides the substantial, material nourishment, Ying Qi provides the subtle, energetic nourishment. Together they travel through all meridians and vessels, nourishing the entire body.
Tongue Signs
Blood Deficiency: The tongue appears pale, often thin and possibly dry. The color lacks the healthy pink-red hue, reflecting insufficient Blood to fill the tongue's vessels.
Blood Heat: The tongue is deep red or crimson, sometimes with red prickles (raised papillae). It may appear dry. In severe cases, the tongue may show bleeding spots.
Blood Stasis: The tongue shows purple discoloration—either the entire body appears purple/dusky, or there are purple spots (petechiae) on the surface. The sublingual veins appear distended, dark, and tortuous. The sides of the tongue may be especially purple, reflecting Liver Blood stasis.
Pulse Signs
Blood Deficiency: The pulse is thin (Xi) and weak, sometimes also choppy (Se). It lacks force and substance, reflecting the insufficient volume of Blood in the vessels.
Blood Heat: The pulse is rapid (Shu) and may be full or surging, reflecting the Heat accelerating Blood movement.
Blood Stasis: The classic pulse is choppy (Se)—uneven, hesitant, rough like a knife scraping bamboo. It may also be wiry (Xian) if Liver is involved, or firm (Lao) if there are masses. The choppy quality reflects obstructed Blood flow.
Deficiency When Xue (Blood) is insufficient
Blood Deficiency (Xuè Xū, 血虚) occurs when the body lacks sufficient Blood to nourish tissues and organs. This can result from inadequate Blood production (Spleen weakness, poor nutrition, chronic illness) or excessive Blood loss (hemorrhage, heavy menstruation, childbirth). Prolonged emotional stress, overwork, or chronic disease can also deplete Blood over time.
When Blood is deficient, tissues become undernourished and dried out. The face becomes pale or sallow, the lips and nails lose color, and the skin becomes dry. The eyes may be dry, vision blurry, and there may be dizziness, especially when standing. Since Blood houses the Spirit, deficiency causes anxiety, poor memory, difficulty concentrating, and insomnia. Without adequate Blood nourishing the tendons, there may be numbness, tingling, muscle cramps, or tremors in the limbs. In women, menstrual periods become scanty or cease entirely. The heart may palpitate due to insufficient Blood to fill and calm it.
Clinical Signs
Related Patterns
Blood Deficiency
General Blood deficiency affecting the whole body with pallor, dizziness, palpitations, and fatigue
Heart Blood Deficiency
Blood deficiency specifically affecting the Heart, causing palpitations, anxiety, insomnia, and poor memory
Liver Blood Deficiency
Liver Blood deficiency causing blurred vision, floaters, muscle cramps, scanty menstruation, and brittle nails
Spleen and Heart Blood Deficiency
Combined pattern from overthinking damaging Spleen's Blood production and Heart's Blood storage
Excess When Xue (Blood) is in surplus
Blood Heat (Xuè Rè, 血热) occurs when pathological Heat enters the Blood level, causing it to move recklessly and potentially escape the vessels. This can result from external Heat invasion that penetrates deeply, internal Heat from Yin deficiency, emotional factors (especially prolonged anger or frustration), or consumption of excessive heating foods and alcohol.
When Heat enters the Blood, circulation accelerates abnormally. The skin may develop red rashes, bleeding under the skin, or hot, red eruptions. Heat agitates the blood, causing it to leave the vessels—manifesting as nosebleeds, blood in urine or stool, heavy menstrual bleeding, or any unexplained hemorrhage. The person feels hot, especially at night, becomes restless and irritable, and may experience fever. The skin may itch intensely. In severe cases affecting the Heart, there may be mental confusion, delirium, or mania.
Clinical Signs
Stagnation When Xue (Blood) fails to flow
Blood Stasis (Xuè Yū, 血瘀) is a critical pathological condition where Blood flow becomes sluggish, obstructed, or stops entirely in certain areas. Stasis can develop from Qi stagnation (since Qi moves Blood), Qi deficiency (weak Qi cannot push Blood), Cold congealing Blood, Heat congealing Blood, trauma, or chronic illness.
The hallmark of Blood stasis is fixed, stabbing pain that worsens at night and with pressure. Unlike the moving pain of Qi stagnation, Blood stasis pain stays in one location and has a sharp, boring quality. The affected area may show purple discoloration, and masses or lumps can form where Blood accumulates. Skin manifestations include purple blotches, spider veins, varicose veins, and a tendency to bruise easily. The complexion becomes dark or dusky, lips and nails turn purple, and sublingual veins become enlarged and dark. In women, menstruation becomes painful with dark blood and clots.
Clinical Signs
Related Patterns
Blood Stagnation
General Blood stasis with fixed stabbing pain, purple discoloration, and masses
Heart Blood Stagnation
Blood stasis in the Heart causing chest pain, palpitations, and purple lips
Liver Blood Stagnation
Blood stasis in the Liver area causing hypochondriac pain, masses, and menstrual problems
Food Stagnation in the Stomach
Uterine Blood stasis causing severe dysmenorrhea, dark clotted blood, and possible masses
Qi And Blood Stagnation
Combined pattern where Qi and Blood both stagnate, common in chronic pain conditions
How to Nourish Xue (Blood)
Diet: Blood-building foods include dark leafy greens (spinach, kale), red and black foods (beets, black beans, dark grapes, goji berries), iron-rich foods (organ meats especially liver, red meat in moderation), dates, eggs, and bone broth. Avoid raw, cold foods that damage Spleen function and impair Blood production.
Lifestyle: Adequate rest is essential—Blood regenerates during sleep when it returns to the Liver. Avoid overwork and excessive mental activity which consume Blood. Moderate exercise promotes circulation, but excessive exercise depletes Blood. Managing stress protects the Liver's Blood-storing function.
Herbal approaches: TCM employs Blood-tonifying herbs like Dang Gui (Angelica), Shu Di Huang (Rehmannia), Bai Shao (White Peony), and He Shou Wu (Polygonum). For Blood stasis, herbs that "invigorate Blood and dispel stasis" are used, such as Dan Shen (Salvia), Tao Ren (Peach Kernel), and Hong Hua (Safflower). Building Spleen Qi simultaneously supports Blood production.
Acupuncture: Points that tonify Blood include ST-36, SP-6, BL-17 (the influential point for Blood), BL-20, and BL-23. For Blood stasis, points that move Blood such as SP-10, LI-4 with LV-3, and local points are used.
Clinical Relevance
Blood pathology appears across virtually all clinical specialties in TCM practice. Blood deficiency commonly presents in patients with chronic fatigue, anxiety, insomnia, menstrual irregularities, or recovery from illness or childbirth. Strengthening Spleen function while directly tonifying Blood addresses root causes.
Blood stasis underlies many chronic pain conditions, cardiovascular diseases, gynecological disorders, and some cancers in TCM perspective. Treatment focuses on "invigorating Blood and dispelling stasis" using appropriate herbal formulas and acupuncture. The recognition that emotional stress causes Qi stagnation leading to Blood stasis helps explain the mind-body connection in chronic illness.
Diagnosis relies heavily on tongue and pulse examination. A pale tongue and thin pulse suggest Blood deficiency; purple tongue with choppy pulse indicates Blood stasis. Treatment always considers Blood's relationships with Qi, Essence, and the organs—particularly the Heart, Liver, and Spleen—for comprehensive, effective therapy.
Classical Sources
Ling Shu (Spiritual Pivot)
Chapter 18 - Ying Wei Sheng Hui (Formation of Nutritive and Defensive Qi)中焦受气取汁，变化而赤，是谓血。
The Middle Burner receives Qi and extracts juice, transforms and changes to red—this is called Blood.
Nan Jing (Classic of Difficulties)
22nd Difficulty气主煦之，血主濡之。
Qi governs warming, Blood governs moistening.
Jing Yue Quan Shu (Complete Works of Zhang Jiebin)
Blood Patterns Chapter血者水谷之精也。源源而来，而实生化于脾。
Blood is the essence of water and grain. It flows continuously, and is actually produced and transformed by the Spleen.
Su Wen (Basic Questions)
Chapter 10 - Wu Zang Sheng Cheng诸血者皆属于心。
All Blood belongs to the Heart.
Modern References
The Foundations of Chinese Medicine
Comprehensive textbook with detailed chapters on Blood physiology, pathology, and treatment in modern TCM practice
Chinese Medical Herbology and Pharmacology
Detailed pharmacological information on Blood-tonifying and Blood-invigorating herbs
A Manual of Acupuncture
Clinical point prescriptions for Blood deficiency, Blood stasis, and Blood Heat conditions