Six Excesses (六淫) Cold Yin External & Internal

Cold as a pathogen

寒邪 Hán Xié · Cold Pathogen
Also known as: Cold Evil · Cold as Pathogenic Factor · Han · External Cold · Exogenous Cold

Cold (Han) is one of the Six Excesses in TCM, characterized by its chilling, congealing, and contracting properties. As a Yin pathogen, it easily damages Yang Qi and causes pain through obstruction of Qi and Blood flow.

Key Properties

Chilling Congealing Contracting Obstructing Slowing Yin in Nature

Season

Winter

Body Layers

Tai Yang

寒邪

Hán Xié

Cold Pathogen

Nature & Properties

Thermal Nature

Cold

Yin-Yang

Yin

Season

Winter

Educational content · Consult qualified TCM practitioners for diagnosis and treatment

Overview

Cold (Hán 寒) is one of the Six Excesses (Liù Yín 六淫) in Traditional Chinese Medicine, representing the dominant climatic influence of winter. As a Yin pathogen with a cold nature, it stands in direct opposition to the body's Yang Qi—the warming, activating energy that keeps bodily functions operating smoothly.

Think of Cold as working like ice in a stream: it slows everything down, causes things to contract and stiffen, and can eventually freeze movement altogether. When Cold invades the body, it impairs circulation, causes muscles and tendons to tighten, and reduces the metabolic fire that keeps organs functioning properly. The classic saying "Cold causes pain" (寒胜则痛) reflects how Cold creates discomfort by obstructing the free flow of Qi and Blood.

Cold pathology can manifest in two main ways: "External Cold" (Wài Hán) from environmental exposure, and "Internal Cold" (Nèi Hán) arising from Yang deficiency within the body. While Winter is the primary season for Cold invasion, modern factors like air conditioning, cold beverages, and inadequate clothing can introduce Cold at any time of year.

Historical Context

The understanding of Cold as a pathogen has deep roots in Chinese medical history. The foundational text Huangdi Neijing (Yellow Emperor's Classic) established that Cold is the dominant Qi of winter and corresponds with the Kidney organ system. The classic statement "Cold injures Yang" became a cornerstone principle of TCM pathology.

The most influential development came with Zhang Zhongjing's Shang Han Lun (Treatise on Cold Damage) written around 200 CE during the Eastern Han Dynasty. This seminal text created the Six Stages framework specifically to understand how Cold-induced diseases progress through the body, from the superficial Tai Yang stage to the deepest Jue Yin level. The Shang Han Lun remains the primary reference for treating Cold-related conditions and its formulas like Ma Huang Tang and Gui Zhi Tang continue to be widely used today.

Later physicians distinguished between the School of Cold Damage (Shang Han) and the School of Warm Diseases (Wen Bing), recognizing that Heat pathogens behave differently from Cold and require distinct treatment approaches.

Defining Characteristics

Injures Yang Qi

寒易伤阳

As a Yin pathogen, Cold directly opposes and damages the body's warming Yang energy. When Yang is weakened, the body loses its ability to maintain warmth and drive metabolic processes, leading to symptoms like cold limbs, fatigue, and reduced organ function. The principle "Yin excess leads to Yang disease" explains this relationship.

Congealing Nature

寒性凝滞

Cold has a congealing, obstructing quality that slows or blocks the movement of Qi, Blood, and body fluids. Just as cold weather can freeze water in pipes, Cold in the body causes stagnation. This obstruction leads to pain—a hallmark symptom of Cold conditions. Pain from Cold characteristically improves with warmth and worsens with cold exposure.

Contracting Property

寒性收引

Cold causes contraction and tightening. It makes the pores close (preventing sweating), vessels constrict, and muscles and tendons stiffen and spasm. This explains symptoms like absence of sweating during cold invasion, muscle cramps, joint stiffness, and difficulty with movement. The classic text states "Cold causes Qi to contract" (寒则气收).

Entry Routes

Cold pathogen can enter the body through several routes:

  • Skin and pores: The primary entry point when exposed to cold weather, wind, or cold water. Cold penetrates the superficial layers first, affecting the Wei (defensive) Qi.
  • Direct organ invasion: Unlike some pathogens that must progress through layers, Cold can directly strike internal organs (called "Zhong Han" or "struck by cold"). This commonly affects the Stomach and Intestines through consuming cold foods/drinks, or the Uterus through cold exposure to the lower body.
  • Neck and back: These areas are particularly vulnerable—the upper back and nape have important acupuncture points that, when exposed to cold drafts, allow Cold to enter easily.

Progression Pattern

Body Layers Affected

Tai Yang

Cold pathology follows characteristic progression patterns depending on the body's resistance:

External Cold progression (Six Stages): When Cold enters from outside, it typically begins at the Tai Yang (Greater Yang) stage, affecting the superficial defensive layer with symptoms like chills, fever, headache, and body aches. If not expelled, it can progress inward through the Yang Ming (Bright Yang) and Shao Yang (Lesser Yang) stages, eventually reaching the three Yin stages (Tai Yin, Shao Yin, Jue Yin) where it becomes increasingly dangerous, damaging organ Yang.

Direct Interior Strike: Sometimes Cold bypasses the exterior entirely and directly attacks internal organs—particularly the Spleen and Stomach (causing vomiting and diarrhea) or the Kidney (causing severe Yang collapse with cold limbs, weak pulse, and exhaustion).

Transformation: When Cold stagnates for prolonged periods, it may transform into Heat, especially when the body's defensive response generates internal fire. This creates complex Cold-Heat mixed conditions.

Clinical Relevance

Cold pathology remains highly relevant in modern clinical practice, with applications spanning acute and chronic conditions:

Acute conditions: Common cold and influenza with Wind-Cold presentation, acute gastroenteritis from cold food/drinks, acute joint pain from cold exposure, and menstrual pain worsened by cold. Early intervention with warming strategies can prevent deeper penetration and complications.

Chronic conditions: Many patients present with underlying Cold patterns from constitutional Yang weakness, chronic cold exposure, or long-term consumption of cold foods and raw diets popular in Western culture. These include chronic digestive weakness, cold-type arthritis and fibromyalgia, chronic fatigue, certain types of infertility, and Raynaud's phenomenon.

Modern considerations: Air conditioning, refrigerated foods, and iced beverages create Cold exposure year-round. Many modern patients unknowingly accumulate Cold through lifestyle choices. Additionally, overuse of antibiotics (considered Cold in nature) can contribute to Cold patterns. Treatment combines herbal medicine, acupuncture with moxibustion, dietary modification (avoiding raw and cold foods), and lifestyle counseling to protect Yang Qi.

Common Manifestations

Aversion to Cold and Chills

The body feels cold and the person seeks warmth, wrapping up in blankets or moving toward heat sources. Unlike heat conditions, the chilly feeling doesn't improve much with covering.

Cold Limbs

Hands and feet become cold, sometimes ice-cold to the touch. In severe cases, coldness can extend to the arms and legs, indicating deeper penetration of Cold into the body.

Pain that Improves with Warmth

Various types of pain—joint pain, abdominal cramping, headache—that characteristically feel better with heat application and worsen with cold exposure.

Absence of Sweating

When Cold closes the pores, the normal sweating response is blocked. This is a key feature distinguishing Cold invasion from Wind-Heat conditions.

Clear, Watery Discharges

Nasal discharge, phlegm, vomit, diarrhea, and urine tend to be clear, thin, and abundant rather than thick or colored—reflecting the cold, watery nature of the pathogen.

Stiffness and Contraction

Muscles feel tight and stiff, joints resist bending, and the neck may be rigid. Movement feels difficult, especially in the morning or after rest.

Abdominal Pain and Diarrhea

When Cold invades the digestive system directly, it causes cramping pain in the abdomen with watery diarrhea, often triggered or worsened by eating cold foods.

Pale Complexion

The face appears pale or even bluish-white, reflecting poor circulation and the body's reduced metabolic warmth.

Tongue Manifestations

The tongue in Cold conditions typically shows:

  • Body color: Pale or bluish-purple, indicating poor circulation and Yang deficiency
  • Coating: White and moist, often thin in early/superficial conditions or thick and slippery in more severe cases
  • Moisture: Wet or even dripping with saliva, reflecting the Yin nature of Cold and accumulation of fluids
  • Shape: May be swollen with teeth marks if Spleen Yang is affected, indicating fluid accumulation from impaired transformation

Pulse Manifestations

Characteristic pulse qualities in Cold conditions include:

  • Tight (Jǐn 紧): The most typical Cold pulse—feels tense and taut like a twisted rope, indicating Cold constriction in the channels
  • Slow (Chí 迟): Fewer than 60 beats per minute, reflecting Cold's slowing effect on circulation
  • Deep (Chén 沉): Found only with pressure, suggesting the pathogen has penetrated to interior levels
  • Floating (Fú 浮): In early-stage external Cold affecting only the surface, the pulse may be floating and tight

Common Pathogen Combinations

The most common pathogenic combination. Wind acts as the carrier that helps Cold penetrate the body's defensive barrier. Wind-Cold invasion causes the classic common cold pattern with chills, headache, body aches, runny nose with clear discharge, and absence of sweating. Wind adds the quality of rapid onset and symptoms that may move around.

A particularly stubborn combination. Cold's congealing nature combines with Dampness's heavy, sticky quality to create conditions that are difficult to resolve. Symptoms include heavy, aching joints (especially worse in damp/cold weather), swelling, feelings of heaviness in the body, and digestive issues. Cold-Dampness commonly affects the Spleen and joints.

When Cold congeals body fluids, it can create Phlegm that is characteristically thin, white, and copious. Cold-Phlegm in the Lungs causes coughing with abundant white watery sputum and wheezing. The Phlegm is easy to expectorate but keeps returning, especially in cold weather.

Differentiation from Similar Pathogens

Cold vs. Internal Cold (Yang Deficiency): External Cold shows predominantly excess symptoms (strong pain, acute onset, tight pulse) with cold signs, while Internal Cold from Yang deficiency shows primarily deficiency symptoms (fatigue, weakness, slow pulse) with cold as a secondary feature. External Cold is treated by expelling the pathogen; Internal Cold requires warming and tonifying Yang.

Cold vs. Blood Stasis: Both can cause pain and purple discoloration. However, Cold pain improves markedly with warmth, while Blood Stasis pain is more fixed and stabbing and may not respond as clearly to heat. Blood Stasis has a characteristic choppy pulse and purple spots on the tongue.

Cold vs. Qi Stagnation: Both cause pain, but Cold pain is relieved by warmth and tends to be cramping or contracting, while Qi Stagnation pain is distending and moves around, often related to emotional stress, and improves with movement or sighing.

Treatment Principles

The fundamental principle for treating Cold is to warm and disperse it. Specific strategies depend on the location and severity:

  • Release the Exterior: For superficial Wind-Cold, use warm, acrid herbs and techniques to open the pores and expel Cold through sweating (diaphoresis).
  • Warm the Interior: For Cold that has penetrated deeper or directly struck internal organs, use hot-natured herbs to warm the affected organs and restore Yang function.
  • Warm the Channels: For Cold lodged in the meridians causing joint or muscle pain, use warming herbs that specifically enter the channels to dispel Cold and promote circulation.
  • Strengthen Yang: When Cold has damaged Yang Qi, combine warming methods with Yang-tonifying herbs to rebuild the body's metabolic fire.
  • Moxibustion: The direct application of heat through moxa is particularly effective for Cold conditions and is often combined with acupuncture.

Representative Formulas

Ma Huang Tang

The primary formula for Wind-Cold invasion with no sweating, fever, chills, and body aches. Powerfully releases the exterior and disperses Cold.

Gui Zhi Tang

For Wind-Cold with sweating, harmonizes the defensive and nutritive Qi. Used when the patient is already sweating but Cold has not been expelled.

Si Ni Tang

Rescues devastated Yang and warms the interior. Used for severe Cold conditions with extremely cold limbs, weak pulse, and exhaustion.

Li Zhong Wan

Warms the Middle Jiao and strengthens Spleen Yang. For Cold in the digestive system with abdominal pain, vomiting, and diarrhea.

Xiao Qing Long Tang

Releases exterior Cold while warming the Lungs and transforming Cold-Phlegm. For Cold invasion with coughing and copious white watery phlegm.

Representative Points

DU-14

Dazhui

Meeting point of all Yang channels. Releases the exterior, expels Cold, and strengthens Yang Qi. Often treated with moxibustion for Cold conditions.
GB-20

Fengchi

Expels Wind-Cold from the head and neck. Relieves headache, stiff neck, and chills from exterior invasion.
LI-4

Hegu

Opens the pores to release exterior pathogens through sweating. Combined with LU-7 for Wind-Cold invasion.
ST-36

Zusanli

Strengthens the Spleen and Stomach, tonifies Qi and Yang. Used with moxa to warm the Middle Jiao in Cold conditions.
REN-4

Guanyuan

Fortifies the original Yang, warms the Lower Jiao. Essential point for treating Kidney Yang deficiency and internal Cold. Best treated with moxa.
DU-4

Mingmen

"Gate of Vitality"—tonifies Kidney Yang and warms the entire body. Key point for addressing the root of internal Cold.

Classical Sources

Huangdi Neijing (Yellow Emperor's Classic)

Su Wen, Chapter 74

寒者，阴之类也。寒则气收。

Cold belongs to the Yin category. When there is Cold, Qi contracts.

Shang Han Lun (Treatise on Cold Damage)

Tai Yang Disease Chapter

太阳病，头痛发热，身疼腰痛，骨节疼痛，恶风无汗而喘者，麻黄汤主之。

For Tai Yang disease with headache, fever, body pain, lower back pain, joint pain, aversion to wind, absence of sweating, and wheezing, Ma Huang Tang governs.

Su Wen (Plain Questions)

Chapter 43, Bi Lun (Painful Obstruction)

痛者，寒气多也，有寒故痛也。

Where there is pain, Cold Qi predominates. There is Cold, therefore there is pain.

Modern References

Chinese Herbal Medicine: Formulas & Strategies

Scheid, Bensky, Ellis & Barolet (2009)

Comprehensive resource on formulas for Cold conditions with classical and modern applications.

Shang Han Lun: On Cold Damage

Mitchell, Ye & Wiseman (1999)

Translation and commentary on the foundational text for understanding Cold pathology and treatment.

The Foundations of Chinese Medicine

Giovanni Maciocia (2015)

Modern textbook with detailed explanation of Cold as a pathogenic factor and its clinical differentiation.