Key takeaways
- For about 15 centuries, Galen’s version of Greek medicine taught Europe and the Middle East that illness came from an imbalance of four body fluids called humors.
- In 1799, doctors trying to rebalance George Washington’s humors drained about half his blood during his final illness, and some have suggested the treatment hastened his death.
- Ayurveda, traditional Chinese medicine and Unani also describe health as balance, and many Indigenous traditions tie wellness to community, spirit and the land.
- When the French physician Pierre Louis counted outcomes in pneumonia patients, those bled early died more often than those bled later, an early lesson in testing a practice instead of trusting a theory.
- Some practices from these traditions show modest benefits in trials, but many herbal products are untested and some contain lead, mercury or hidden drugs, so tell your clinician what you take.
On December 12, 1799, George Washington spent about five hours outside in rain, snow, hail and wind1. He didn’t change out of his wet clothes before dinner1. On Saturday morning he woke with a fever and struggled to breathe1.
He knew what to ask for. Washington told his overseer to bleed him1. Three doctors attended him, and on his last day he was bled four times1. In all, he lost about three quarts of blood, roughly half of what his body held1.
A younger doctor, Elisha Dick, objected to so much bleeding and proposed a new surgery to open the airway1. The senior doctors overruled him1. Some have suggested the bleeding, purges and blistering hastened Washington’s death1.
His doctors were not careless. They were following one of the oldest ideas in medicine: illness is an imbalance, and healing means restoring balance. In their view, excess blood, phlegm and bile fueled fever and inflammation, so draining them made sense1.
Versions of that balance idea guided healers around the world for thousands of years. Looking at them side by side shows what many traditions shared, what science later supported and what it set aside.
Four humors guided Western medicine for about 1,500 years
In Greece in the fifth century BCE, physicians linked to the name Hippocrates taught on the island of Cos2. They are credited with turning medicine away from the gods and toward close observation of the body2.
Their core idea was the four humors: blood, phlegm, yellow bile and black bile2. When these fluids fell out of balance, illness followed2. Treatment could mean a change of diet, a medicine, bloodletting or purging2.
Each humor carried qualities. Blood was hot and moist, yellow bile hot and dry, black bile cold and dry, and phlegm cold and moist3. Each was also tied to a season: blood to spring, yellow bile to summer, phlegm to autumn and black bile to winter3.
In the second century CE, the physician Galen, who once treated gladiators and later served the emperor Marcus Aurelius, carried these ideas forward2. His writings stood for Greek medicine across Europe and the Middle East for about 15 centuries, and in the West his theories hardened into dogma2.
Humoral thinking shaped European medicine until at least the 1700s3. As Washington’s final illness shows, it shaped American bedsides too1.
Unani carried Greek medicine east, and it is still practiced
Greek medicine did not vanish when Rome fell. Western Europe lost most of the texts, then recovered many in the 1300s and 1400s, partly through Arab centers of learning2.
In Arab and Persian lands, the Greek system grew into what is now called Unani medicine10. The name comes from the word for Ionia, or Greece10. Unani reached the Indian subcontinent about a thousand years ago and is now one of India’s recognized medical systems10.
Unani keeps the four humors under its own names: dam (blood), balgham (phlegm), safra (yellow bile) and sauda (black bile)10. Health depends on a balance of elements, humors and temperament, called mizaj10.
Its most practical teaching may be the six essentials of health. These are air, food and drink, physical activity and rest, mental activity and rest, sleep and waking, and the retention and elimination of wastes10.
Unani also holds that every person has an inborn power of self-preservation10. Practitioners read the pulse, urine and stool to judge a patient’s state10.
Ayurveda reads the body through three doshas
The World Health Organization (WHO) lays out Ayurveda’s core ideas in its benchmarks for training Ayurveda practitioners, a guide for countries that regulate the practice6. The document sets training standards. It does not judge whether the treatments work.
According to those benchmarks, the system took shape in the Indian subcontinent between about 2000 and 1500 BCE, and it is now the most widely practiced traditional medicine in South Asia6. The classical author Charaka called Ayurveda the knowledge of life6.
Ayurveda names five basic elements: space, air, fire, water and earth6. Three doshas, called vata, pitta and kapha, keep the body’s functions in balance through motion, transformation and building up6. When their work is disturbed, disease follows6.
Each person has a constitution, or prakriti, a personal makeup of body, mind and behavior6. In Ayurveda, health means physical, mental and spiritual well-being, and the WHO benchmarks note that staying healthy takes the person’s own active effort6. Care can include counseling, diet, medicines, procedures and surgery, plus five cleansing procedures, called panchakarma, that include induced vomiting and enemas6.
In the United States, about 240,000 adults use Ayurvedic medicine, and no state requires its practitioners to hold a license, according to a 2019 page from the National Center for Complementary and Integrative Health (NCCIH)7.
Chinese medicine seeks harmony between yin, yang and qi
Traditional Chinese medicine grew out of the ancient philosophy of Taoism, and NCCIH traces its history back more than two and a half millennia8. In this view, each person is the universe in miniature8.
Two forces, yin and yang, oppose and complete each other8. Health comes from harmony between them, and illness from imbalance8. The five elements, wood, fire, earth, metal and water, stand for all things in nature, including the body’s normal workings and its changes in disease8. Qi, a life energy said to circulate through the body, keeps its functions going8.
NCCIH draws a careful line here. The research it funds sets these ideas aside and tests specific practices for their effects on the body and on symptoms8. That habit is useful for anyone weighing a tradition.
Our article on traditional medicine research looks at how fairly these practices have been tested.
Many Indigenous traditions tie health to community, spirit and land
Native peoples are many distinct nations, not one group, and their healing ways differ widely11. In the National Library of Medicine’s Native Voices exhibit, Native people describe health in their own words, and some values come up again and again: reverence for nature, tradition and the spiritual world, personal responsibility, and the ties between communities11.
Healers featured in the exhibit often say the patient does most of the healing, with the healer as a guide and counselor12. Staying well is described as a serious, lifelong duty12. Healing can draw on stories, humor, music, tobacco, smudging and ceremony, and it reaches past the person to family, community and future generations12.
The Indian Health Service (IHS) has written support for traditional healing into policy. A 1994 IHS policy told staff, when patients ask, to help them reach a traditional practitioner and to make room and privacy for ceremonies13. It also told staff to avoid uninvited questions about patients’ private beliefs13.
The same policy recognized that each tribe’s or village’s own culture defines its practices13. That is why this article stays general. Our articles on group healing practices and on white sage cover how to learn with respect.
A life force ran through many systems, but biology found it didn’t need one
Many of these systems share another idea: a life force that sets living things apart. Philosophers call this vitalism, the belief that a non-physical force, beyond ordinary chemistry and physics, sustains life14. In the Hippocratic tradition, vital forces were tied to the temperaments and humors14.
Qi in Chinese medicine and the self-preserving power in Unani reflect a similar instinct810. So did early chiropractic’s “Innate Intelligence,” an idea from its founder, D.D. Palmer14.
Science moved on slowly. In 1828, the chemist Wöhler made urea, a substance the body produces, in a laboratory, which dealt vitalism a serious blow14. The evolutionary biologist Ernst Mayr pointed to Darwin’s theory and the rise of genetics as even bigger reasons for its decline14.
Modern biology explains life without a separate force14. That doesn’t erase what these traditions noticed. Your body does repair itself, and caring for that ability is wise. Science simply describes it with cells, genes and chemistry.
Bloodletting lost its grip when someone counted
For centuries, few healers checked whether their treatments worked. In France, the physician Pierre Louis did4.
Bleeding was booming there. France brought in 42 million medical leeches in 1833 alone4. Louis tracked 77 patients who had the same kind of pneumonia. Forty-one were bled in the first four days of illness, and 36 from the fifth day on4.
Louis himself found the result startling4. Of the patients bled early, about 44% died. Of those bled later, 25% died4.
He reported the work in 1828 and expanded it into a book in 1835. His verdict: bloodletting had only a small, limited role4.
That habit of counting outcomes is the heart of how medicine tests treatments today. It also explains why bloodletting survives in one place where it clearly works.
People with hemochromatosis store too much iron. For them, doctors remove about a pint of blood on a regular schedule5. The National Institutes of Health calls it “the most direct and safe way to lower body stores of iron”5.
The threads these traditions share
| Tradition | Roots | What health means | Key ideas | Daily-life focus |
|---|---|---|---|---|
| Greek humoral medicine | Cos, 5th century BCE; Galen, 2nd century CE2 | Balance of four humors2 | Hot, cold, moist, dry; seasons3 | Diet and regimen2 |
| Unani | Greek roots, grown in Arab and Persian lands; in India about 1,000 years10 | Balance of elements, humors and temperament10 | The body’s self-preserving power10 | Six essentials, from air to sleep10 |
| Ayurveda | Indian subcontinent, about 2000–1500 BCE6 | Well-being of body, mind and spirit6 | Five elements, three doshas, prakriti6 | Diet, counseling, personal effort6 |
| Traditional Chinese medicine | Taoist roots, more than 2,500 years8 | Harmony of yin and yang8 | Qi; five elements8 | Practices such as tai chi9 |
| Many Indigenous traditions | Many distinct nations, each with its own ways11 | Wellness tied to nature, spirit and community11 | The patient as the main healer12 | Ceremony, stories, family, community12 |
Three threads run through these traditions. Health is more than the absence of disease, and the Greek, Unani, Ayurvedic and Chinese systems all describe it as balance. The person is part of something larger: the seasons, the cosmos, a community or the land. And everyday practices, from meals and sleep to movement and ceremony, sit close to the center of care.
Science has come around on part of this. Your body runs on circadian rhythms, roughly 24-hour cycles set mainly by light and dark, and also by food, stress, activity and temperature, according to the National Institute of General Medical Sciences15. These rhythms help regulate sleep, hormones, appetite, digestion and body temperature15.
Researchers won the 2017 Nobel Prize for work on how these internal clocks run15. Long-term disruption, as with shift work or constant jet lag, can raise the risk of obesity, diabetes, mood disorders and heart problems15.
If these traditions draw you because they see you as a whole person, living in a place, a family and a season, you are in good company. That view has aged well. Their specific explanations, such as humors or doshas, work best as old maps: worth studying for where they point, but not literal pictures of the body.
How the old ideas hold up today
| Idea or practice | Rating | What the evidence shows |
|---|---|---|
| Bleeding for fever, pneumonia or general illness | Early bleeding was linked to more pneumonia deaths in Louis’s study4; heavy bleeding may have hastened Washington’s death1 | |
| Removing blood for iron overload (hemochromatosis) | It is the main, standard treatment5 | |
| The body follows daily rhythms tied to light, meals and sleep | Body clocks steer sleep, hormones and digestion, and long-term disruption can raise disease risk15 | |
| Acupuncture for some chronic pain | May help low-back, neck and knee pain, but real and sham needling often perform about the same9 | |
| Tai chi for balance in older adults | May improve balance and ease knee osteoarthritis pain9 | |
| Ayurvedic herbal formulas | Most trials are small or poorly designed; some products contain lead, mercury or arsenic7 | |
| Chinese herbal products | Many studies are poor quality; some products have held hidden drugs or heavy metals9 | |
| Qi, doshas or a separate vital force exist as physical things in the body | NCCIH studies practices, not these concepts8; biology no longer needs a vital force14 |
Questions readers ask
Is Unani medicine the same as Greek humoral medicine?
They share roots. Unani grew from Hippocratic medicine in Arab and Persian lands and keeps the four humors under its own names10. It has kept developing for centuries, including in India, where it is a recognized system today10.
Was bloodletting ever useful?
For most illnesses, no, and Louis’s pneumonia counts pointed the other way4. But removing blood on a careful schedule is the main treatment for hemochromatosis, an iron-overload condition5.
Do Ayurveda and Chinese medicine describe the same thing in different words?
They overlap in spirit, since both see health as balance and both list five elements68. But the elements differ, and the systems grew from different philosophies, so it is fairer to treat them as separate traditions.
Why doesn’t science test qi or doshas directly?
Agencies such as NCCIH test what a practice does for people, such as whether acupuncture eases back pain, rather than the theory behind it89. A practice can help even if its traditional explanation isn’t literal, and a convincing theory can still cause harm, as bloodletting did.
How can I learn about Native healing ways respectfully?
Start with sources created with Native communities, such as the Native Voices exhibit1112. Ceremonies and specific healing knowledge belong to the nations that keep them, so follow their guidance on what is open to outsiders.
The bottom line
Healers in Greece, Persia, India, China and Native nations saw health as more than a body free of disease. They tied it to the mind, the community and the world around us. That big picture has held up better than many of the specific theories built on it.
The lesson from Washington’s bedside and Louis’s ward is simple. Honor a tradition’s wisdom, and still ask what happens to the people who use its treatments. When you do both, you keep the best of the past without repeating its mistakes.
Related reading
About this article
This article was researched from National Library of Medicine exhibitions, NIH institute pages, Indian Health Service policy, World Health Organization and Indian government sources, and peer-reviewed history, all listed below. It was reviewed in October 2026. It is general education and not medical, legal or financial advice.
Sources
- National Library of Medicine. “At Journey’s End,” in “Every Necessary Care and Attention: George Washington & Medicine.” Online exhibition. nlm.nih.gov
- National Library of Medicine. “Greek Medicine.” History of Medicine, 2022. nlm.nih.gov
- National Library of Medicine. “And there’s the humor of it: Shakespeare and the Four Humors.” Online exhibition, 2023. nlm.nih.gov
- Morabia A. “Pierre-Charles-Alexandre Louis and the evaluation of bloodletting.” The James Lind Library, 2004. jameslindlibrary.org
- National Institute of Diabetes and Digestive and Kidney Diseases. “Treatment of Hemochromatosis.” NIH, reviewed 2020. niddk.nih.gov
- World Health Organization. “WHO benchmarks for the training of ayurveda.” WHO, February 2022. who.int
- National Center for Complementary and Integrative Health. “Ayurvedic Medicine: In Depth.” NIH, 2019. nccih.nih.gov
- National Center for Complementary and Integrative Health. “Traditional Chinese Medicine: In Depth.” NIH, updated 2013. files.nccih.nih.gov
- National Center for Complementary and Integrative Health. “Traditional Chinese Medicine: What You Need To Know.” NIH, 2019. nccih.nih.gov
- Directorate of AYUSH, Government of NCT of Delhi. “Unani Medicine.” ayush.delhi.gov.in
- National Library of Medicine. “Healing Ways,” in “Native Voices: Native Peoples’ Concepts of Health and Illness.” Online exhibition. nlm.nih.gov
- National Library of Medicine. “Medicine Ways: Traditional Healers and Healing,” in “Native Voices.” Online exhibition. nlm.nih.gov
- Indian Health Service. “Special General Memorandum 94-08: Statement of Policy for the Traditional Cultural Advocacy Program.” IHS, 1994. ihs.gov
- Simpson JK, Young KJ. “Vitalism in contemporary chiropractic: a help or a hinderance?” Chiropractic & Manual Therapies, 2020. link.springer.com
- National Institute of General Medical Sciences. “Circadian Rhythms.” NIH, updated 2025. nigms.nih.gov