In TCM, health is seen as the balance between the body’s internal environment and the external world. Disease occurs when pathogenic factors (Xie Qi) invade or disturb the normal functioning of Vital Qi (Zheng Qi). These factors are categorized into External (climatic/environmental) and Internal (emotional/psychological) causes.

🌪️ A. External Pathogenic Factors (Six Evils or Six Climatic Factors)

These are climatic influences from the environment that can invade the body, especially when Wei Qi (Defensive Qi) is weak.

1. Wind (Feng)

• Nature: Yang in nature, mobile, fast, the leader of all evils.

• Season: Spring.

• Organ Affected: Liver, skin, upper body.

• Symptoms:

  • Sudden onset of symptoms (e.g., chills, fever, aversion to wind)

  • Moving pain (e.g., wind-damp Bi syndrome in joints)

  • Involuntary movements (e.g., tremors, convulsions)

  • Itchy skin, rashes

• Pathologies:

  • Wind-Cold

  • Wind-Heat

  • Wind-Damp

2. Cold (Han)

• Nature: Yin in nature, contracts, slows down, impairs Yang.

• Season: Winter.

• Organ Affected: Kidneys, Spleen, Stomach.

• Symptoms:

  • Chills, aversion to cold

  • No sweating, body aches

  • Cold limbs, pale complexion

  • Diarrhea, abdominal pain

• Pathologies:

  • Cold invading channels → pain/stiffness

  • Cold invading Stomach → vomiting, epigastric pain

  • Cold affecting uterus → infertility, menstrual pain

3. Dampness (Shi)

• Nature: Yin in nature, heavy, sticky, lingering.

• Season: Late summer or humid conditions.

• Organs Affected: Spleen, Lower Jiao.

• Symptoms:

  • Heavy limbs, fatigue, foggy mind

  • Sticky tongue coating, poor appetite

  • Loose stools, vaginal discharge

  • Swelling, edema

• Pathologies:

  • Damp-Heat → urinary infection, skin eruptions

  • Damp-Cold → digestive issues, joint pain

  • Damp obstructing channels → Bi Syndrome

4. Heat/Fire (Re)

• Nature: Yang in nature, ascends, dries fluids, stirs wind.

• Season: Summer.

• Organs Affected: Heart, Liver, Lung.

• Symptoms:

  • Fever, red face, irritability

  • Thirst, constipation, dark urine

  • Mouth ulcers, bleeding

  • Rapid pulse, red tongue

• Pathologies:

  • Excess Heat: acute inflammation

  • Internal Fire: emotional disturbance, insomnia

  • Heat in Blood: skin rashes, nosebleeds

5. Dryness (Zao)

• Nature: Yang in nature, injures Yin and fluids.

• Season: Autumn.

• Organs Affected: Lungs.

• Symptoms:

  • Dry skin, dry mouth, dry cough

  • Thirst, constipation

  • Scanty urine, dry nose

• Pathologies:

  • External Dryness: affects lungs → dry cough, sore throat

  • Internal Dryness: chronic dehydration of fluids

6. Summer Heat (Shu)

• Nature: Yang, extreme heat, ascends and disperses.

• Season: Summer.

• Organs Affected: Heart, Lungs.

• Symptoms:

  • High fever, sweating

  • Thirst, irritability

  • Dizziness, exhaustion

  • Heatstroke symptoms

• Often combines with Dampness in tropical climates.

💢 B. Internal Pathogenic Factors (Emotional Causes of Disease)

These refer to excessive or prolonged emotional states that affect the internal organs and disrupt Qi, Blood, and organ function.

1. Anger (Liver)

• Causes Liver Qi to rise or stagnate.

• Symptoms: Headaches, red face, dizziness, irritability, menstrual irregularities.

• Can lead to Liver Fire, hypertension, or stroke.

2. Joy (Heart)

• Excessive joy scatters Heart Qi.

• Symptoms: Palpitations, overexcitement, insomnia, mental restlessness.

• Overstimulation (e.g., mania) can cause Shen disturbance.

3. Sadness (Lungs)

• Weakens Lung Qi and disperses it.

• Symptoms: Shortness of breath, fatigue, crying, chest tightness.

4. Worry/Overthinking (Spleen)

• Knots Qi and impairs the transformation and transportation function.

• Symptoms: Poor appetite, loose stools, fatigue, abdominal distension.

5. Fear (Kidneys)

• Makes Qi descend suddenly.

• Symptoms: Incontinence, night sweats, kidney weakness, anxiety.

• In children: may cause bedwetting or developmental issues.

6. Shock (Heart & Kidneys)

• Sudden fright scatters Heart Qi and depletes Kidney Essence.

• Symptoms: Palpitations, insomnia, memory issues, stammering.

🧠 Emotional Impact on Organs:

📌 Summary Table of External vs. Internal Factors: