TCM categorizes disease causes into three main groups: external pathogens that invade from the environment, internal emotions that damage organs directly, and lifestyle factors that deplete the body over time. Each group has specific patterns and signatures — which is why TCM practitioners ask about your emotional life and daily habits, not just your symptoms.
The Six Exogenous Pathogens 六淫
Wind, Cold, Summer Heat, Dampness, Dryness, and Fire are the six climatic forces that, in excess or at the wrong time, become disease-causing pathogens. In normal amounts, they're just weather. As pathogens (邪氣), they invade through the skin and pores, mucous membranes, or mouth and nose — triggering exterior patterns first, then penetrating deeper if the body's defensive Qi (Wei Qi) can't repel them.
The Seven Emotions 七情
Internal causes of disease in TCM are primarily the seven emotions. Unlike external pathogens that invade the body from outside, emotions damage organs directly from within — specifically by disrupting the upward/downward/inward/outward flow of Qi. The damage happens not from feeling these emotions occasionally, but from their extreme intensity or prolonged duration.
| Emotion | Organ Damaged | Qi Movement | Clinical Patterns |
|---|---|---|---|
| Joy喜 · Xǐ | Heart 心 | Qi slackens (氣緩) | Excessive excitement → scattered attention, palpitations, hypomania, mental instability |
| Anger怒 · Nù | Liver 肝 | Qi rises (氣上) | Flushed face, red eyes, headache, hematemesis — in severe cases, fainting from Qi surging upward |
| Pensiveness / Worry思 · Sī | Spleen 脾 | Qi knots (氣結) | Overthinking stagnates Spleen Qi: poor appetite, bloating, weak digestion, forgetfulness |
| Grief / Sadness悲/憂 · Bēi/Yōu | Lung 肺 | Qi dissolves (氣消) | Chronic sadness depletes Lung Qi: shortness of breath, fatigue, lowered immunity, crying without cause |
| Fear恐 · Kǒng | Kidney 腎 | Qi descends (氣下) | Chronic fear depletes Kidney Qi: urinary incontinence, low back weakness, sexual dysfunction |
| Fright / Shock驚 · Jīng | Heart & Kidney | Qi scatters (氣亂) | Sudden shock scatters Qi and disturbs Shen: palpitations, insomnia, anxiety, startling easily |
The five-to-seven-emotion distinction matters: the foundational five (joy, anger, pensiveness, grief, fear) each map to one of the Five Zang. Fright (驚) is sometimes listed separately from fear because it's acute-onset while fear is chronic. Both primarily affect the Heart and Kidney.
Lifestyle Factors
Beyond environment and emotions, TCM recognizes a category of causes that are purely about how you live — dietary patterns, physical exertion, sexual activity, and rest. These don't cause dramatic acute diseases, but they silently deplete the body over years.
Phlegm and Blood Stasis
These are not primary causes but derived pathogens — formed when primary causes remain unresolved. Once formed, they become powerful causes of disease themselves.
"Wind is the leader of all diseases — it opens the way for every other pathogen to enter."
Reading Disease Causes in Daily Life
TCM's etiology framework turns everyday observations into clinical clues. Waking at 3 AM every night? The Liver time (1–3 AM) is disturbed — look for Liver Qi stagnation or Blood deficiency. Catching every cold that circulates? Wei Qi deficiency, often from Lung weakness. Chronic migraines that worsen with stress? Liver Qi rising — the anger pathogen even when no anger is felt.
The emotion-organ connections are particularly useful for understanding psychosomatic patterns. The Spleen's link to pensiveness explains why academic overload reliably causes digestive issues. The Lung's link to grief explains the breathlessness and immunity drops during bereavement. These aren't metaphors — TCM treats them as literal physiological mechanisms.
Understanding disease causes doesn't mean living in fear of weather or emotions. It means reading your symptoms in context — seeing the pattern behind the complaint, and addressing root causes rather than just suppressing signs.