There is an organ in your body that never complains. It asks for nothing. It makes no sound, sends no warning when you push it too hard, and simply keeps working, day and night, for years, while you live. You think of your heart, because you feel it beat. You think of your lungs, because you feel them breathe. But this organ you almost never think of. Precisely because it does its work so quietly.

The liver.

What moves me, again and again, is this: thousands of years ago people thought the liver so important that they looked for their gods inside it. And today we have all but forgotten it. Perhaps our ancestors knew more than we think – and, at the same time, less than they believed. That pattern, from revered to forgotten, runs like a thread through this whole story. Hold on to it.

In my work at the hospital I come close to everything this organ endures. Let’s look at it calmly today, not as a patient, but as someone who wants to understand their own body a little better. We begin five thousand years ago.

The seat of life

Picture this: ancient Babylon, somewhere around 1900 to 1600 BC, almost four thousand years ago. A priest sacrifices a sheep, lifts out the liver and bends over it intently. Not to cook it. To read the future.

This was no fringe superstition. It was serious affairs of state. Babylonian and Assyrian kings would start no war, treat no illness and make no important decision before a trained diviner — a bārû — had studied the liver. The art is called hepatoscopy: foretelling from the liver. The British Museum even holds a clay model of a sheep’s liver from that era, covered in holes and inscriptions, used as study material for trainee diviners.

Why the liver, of all organs? Because in a slaughtered animal it is the organ most filled with blood. And blood, these civilisations understood instinctively, is life. So the liver simply had to be the seat of life, the place where the gods showed their will most clearly.

They were wrong about the divination. But about the importance of the organ? There they were astonishingly close to the truth.

Prometheus, and an honest caveat

Jump forward a few centuries, to Greek mythology. There you’ll find the most famous liver story of all time.

Prometheus, the Titan who stole fire from the gods and gave it to humankind, is punished by Zeus. Chained to a rock, each day an eagle comes to eat his liver. And every night the liver grows back, ready to be devoured again the next morning. An endless torture, but also, if you look closely, a strikingly accurate picture of something we now genuinely know: the liver can repair itself.

Here it becomes tempting to cry: “See, the ancient Greeks already knew!” And you’ll read exactly that everywhere.

But now comes the part I want to be honest about, because that is part of how I write.

When scientists looked into this seriously, they found no convincing evidence that the Greeks truly understood that the liver regenerates (Annals of Internal Medicine, 2008). The art of reading the liver taught them something about the shape of the organ, not its function. Real knowledge of liver repair required anatomical research they simply did not yet have. The actual discovery is only nineteenth-century, and the first real experiment, in which two-thirds of a rat’s liver was removed to see what grew back, dates from 1931.

In other words: it is not lost ancient wisdom. It is a beautiful coincidence. The myth touched the truth without knowing it.

(And if it delights you: the old sources couldn’t even agree on how often the eagle came. Hesiod wrote “every day”, Aeschylus “every other day”. Two poets, two different recovery times, and neither had ever measured it.)

Older than every myth

The liver itself, by the way, is far older than Babylon or Greece. It is ancient.

Picture a transparent, finger-length sea creature: the lancelet (amphioxus), a distant relative of all vertebrates. It has no true liver, but it does have an outgrowth of the gut that looks surprisingly similar. Research showed that this “liver pouch” and our liver are in fact the same organ, only grown apart over hundreds of millions of years (Nature Ecology & Evolution, 2024).

After that, the liver built up its talents bit by bit. Making bile, clotting blood, those functions were added along the way, often because genes were copied and the copy took on a new task. The thread running through fish, frog, bird, mouse and human: the blueprint stayed remarkably faithful. A design that works is not one evolution lets go of easily.

A pantry that loves to stockpile

But what does the liver actually do, that so impressed the ancients?

If I had to compare it to something, it would be a cross between a well-stocked pantry and a purification plant. The pantry stores what you’ll need later: sugar (as glycogen), vitamins, minerals. The purification plant removes what is harmful: medicines, alcohol, waste products. And the remarkable thing is that the liver does this with enormous devotion. It keeps storing, even when it’s really becoming too much.

And there lies a shadow side. Sometimes the liver stockpiles so faithfully that it makes itself ill.

In the hereditary disease haemochromatosis, too much iron builds up; in Wilson’s disease, too much copper. In both cases the stored metal slowly damages the very organ that kept it so dutifully (Med Clin North Am, 2014). The same goes for fat: when more fat is stored than is good for it, the liver can grow fatty, one of the most common liver conditions of our time.

The lesson is almost human: faithfully bearing a load is a virtue, until the burden begins to wreck the system itself.

The polar bear and a Dutch ship from 1597

That stockpiling can become extreme. Take the polar bear.

Polar bears eat mostly seals, rich in fat. That fat contains a great deal of vitamin A, and the polar bear stores the surplus in its liver, in quantities that make the organ outright toxic to humans. The Inuit have known this for a very long time and consistently leave the polar bear’s liver alone.

And here comes a story closer to home than you’d expect. In 1596 the Dutch explorer Willem Barentsz and his crew became frozen in on Nova Zembla. They wintered in a self-built house, besieged by polar bears. When they killed one and ate its liver, the men became sicker than they had ever been, fever, dizziness, and as they recovered their skin began to peel away in strips. Ship’s officer Gerrit de Veer recorded it in his diary. With that, he was probably the first Westerner to write down what we now know as vitamin A poisoning (New England Journal of Medicine, 2003).

A sober disaster, centuries before vitamin A was even discovered. The animal’s liver had simply done its job too well.

That same principle, in fact, explains something you may have sitting in your kitchen cupboard. Look at the label of a multivitamin: the amount of vitamin A is often deliberately kept around half the daily requirement or lower, and sometimes partly as beta carotene, a precursor your body only converts when it needs it. That is no accident. Because you also take in vitamin A from your food every day, and because the liver stores it, makers often keep the supplement modest, so it doesn’t quietly accumulate. The same caution the Inuit knew centuries ago now sits hidden in a dosage table. (Staying honest: it varies by brand, so do check your own label.)

More languages than we can count

You’ll often read that the liver has “more than 500 functions”. Honestly: that number isn’t an exact tally, but a way of saying how versatile it is. No one has a complete list, and anyone who presents it as hard fact is selling you a false certainty.

What we do know well are its most important tasks. The top ten:

1. Keeping blood sugar stable — storing sugar as glycogen and releasing it when you need it.
2. Fat metabolism — processing fats and producing cholesterol.
3. Making proteins — including albumin, which keeps your blood in balance.
4. Producing bile — essential for absorbing fats from your food.
5. Detoxifying — breaking down medicines, alcohol and toxins.
6. Neutralising ammonia — converting it into urea, which you pass in urine.
7. Making clotting factors — so a small wound stops bleeding.
8. Storage — of vitamins (A, D, B12) and minerals (iron, copper).
9. Defence — special cells (Kupffer cells) clear bacteria and old cells from your blood.
10. Clearing and regulating — breaking down old red blood cells and keeping hormones in balance.

Ten indispensable jobs, in one quiet organ, without a pause. No wonder the Babylonians thought life itself was seated here.

How long can you go without it?

Not long. And that is what makes the liver so especially vulnerable, and so impressive.

In acute liver failure, the liver’s function drops away in a short time. That is life-threatening, often within days to weeks. For the kidneys we have dialysis, a machine that temporarily takes over the work. For the liver, no such full replacement exists. There are supportive techniques that can bridge someone over, but the only real solution in complete liver failure is a transplant (The Lancet, 2024).

No machine can imitate all those hundreds of tasks at once. That says something about how incredibly integrated this organ is.

The organ that comes back — and when it doesn’t

And then the most hopeful part, the bit where Prometheus was accidentally right. The liver can repair itself.

It is the only internal organ that, after damage, grows back to roughly 100% of what your body needs. Scientists call this the hepatostat, a kind of internal thermostat that returns the liver to exactly the right size (Nature Reviews Gastroenterology & Hepatology, 2021). In a living donor, up to around 70% can be removed, after which the organ largely grows back within weeks.

But — and this is the honest caveat — that holds for a healthy liver, with one off damage. Under prolonged strain (alcohol, fat, viruses) something else happens. The repair tissue is replaced by scar tissue: connective tissue, not a working liver cell. That is how cirrhosis eventually develops, and then the liver can no longer spring back.

Prometheus’s eagle came every night, and every night everything grew back. In real life it works just as long, until it doesn’t.

Alcohol: why one person falls ill sooner than another

This is perhaps the most frequently asked question. Two people drink roughly the same amount for years. One develops a diseased liver, the other doesn’t. How can that be?

Science gives a surprisingly nuanced answer here. Of the people who drink heavily over a long time, only a minority develop cirrhosis. The risk is, of course, linked to how much and how long someone drinks, but that explains far from everything.

Part of the predisposition lies in your genes. In a large study, people with such an unfavourable genetic score and diabetes turned out to have more than ten times the chance of alcohol-related cirrhosis compared with people without those risk factors (Journal of Hepatology, 2022). Other large scale genetic research showed that people with the highest genetic predisposition run a 2.5 to 6 times higher risk of fatty liver, cirrhosis and liver cancer (Nature Genetics, 2023).

So: dose and duration matter, but so do your genes, your sex (at the same amount, women on average take damage sooner), your weight, diabetes and whatever else your liver already has to put up with. That is why one person falls ill young and another only in old age — or never.

What this is not: a free pass. That your neighbour still has a glass every evening at eighty says nothing about your liver. And a safe amount is something I deliberately can’t name here, that depends too much on the person. Do you have concerns about this for yourself? Talk to your GP, who can look at your own situation with you.

The eagle that waits thirty years

What I find so fascinating about the liver is exactly what makes it so treacherous. It is incredibly forgiving. Someone can be reasonably fit for years while, beneath the surface, all sorts of things are changing: fat, inflammation, the first scar tissue. And then it comes, sometimes seemingly out of nowhere. To the patient it feels abrupt. For the liver it was often a process of ten, twenty, thirty years.

If Prometheus lived today, the eagle wouldn’t eat his liver in a single day. It would offer him a few glasses every evening, and then wait patiently for thirty years.

And yet, let’s stay honest and balanced here too, almost everyone drinks something now and then, and most people don’t fall ill from it. Alcohol is woven deep into birthdays, weddings, New Year’s Eve, a sunny terrace. Criticism of alcohol therefore feels, to many people, like criticism of conviviality itself. I understand that. So this passage is not a wagging finger. It is an invitation to look, just once, consciously at something we usually take for granted.

Because something is shifting. In many Western countries, alcohol use among young people has been falling for over twenty years, visible in long-running research such as the American Monitoring the Future study. Researchers point to greater health awareness, better alcohol-free alternatives and different ways of being together. Staying honest: some analyses expect this generation to drink somewhat more again as it ages, so it is no settled turning point. But the old taken-for-grantedness is gone.

With big health changes you often see a pattern, not a law, but a recurring shape. First, something is utterly normal (“everyone does it”). Then doubt arises. Then scientific consensus. And finally a cultural shift, after which a new generation is amazed that we ever found it normal. With smoking we have largely reached that last phase; there were once even doctors in cigarette adverts.

Think of the Marlboro cowboy. For nearly half a century, from the 1950s to 1999, a single image sold cigarettes to millions of men: a weathered cowboy in a vast landscape, no words needed. Smoking equalled rugged, free, independent, in short, being a man. (An amusing detail: before the cowboy, Marlboro was actually marketed as a women’s cigarette.) And then, within a few decades, that image all but vanished. What was once the height of toughness became something to feel a little embarrassed about. Some of the men who played the cowboy later died of smoking-related diseases, the image of strength and health sold precisely the opposite. The image didn’t tip over because of a single ban, but because it slowly lost its shine.

With alcohol, many societies are somewhere in the middle of that. Whether, and when, it tips, no one knows for sure.

Nor do I.

In closing

The liver is, as far as I’m concerned, the most underrated organ you have. Modest, versatile, forgiving. A workhorse that keeps bearing the load for years, that rebuilds itself, that gets damaged and begins again, until the burden is too heavy for too long.

Perhaps that’s also why this organ moves me so. It resembles the story of many people. Of those who had to start over after a loss. Of parents. Of anyone who, at a difficult moment, discovered they could carry more than they thought.

Five thousand years ago, people saw the liver as the seat of life. They looked for the wrong thing in it, the will of the gods, but they sensed something that science can only now fully explain: that there is something special here. Perhaps our ancestors were less far from the truth than we think.

And then one question remains, far beyond biology, to sit with tonight: what do you carry so faithfully that you no longer feel when it’s becoming too much?

This article is meant to inform and to spark a little wonder — it is not medical advice. Do you have questions or concerns about your own health? Please discuss them with your GP or a treating specialist.

Related reading

• What Really Happens During a Hangover
• Liquid Gold, or Liquid Marketing?
• Diets: What Really Works?

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Sources

The scientific articles below were found via PubMed; the DOI links point to the original publications. Historical sources are indicated as such.

1. Power C, Rasko JEJ. Whither Prometheus’ liver? Greek myth and the science of regeneration. Ann Intern Med. 2008;149(6):421–426. DOI — the honest caveat: no convincing evidence the Greeks knew about regeneration.
2. Higgins GM, Anderson RM. Experimental pathology of the liver. I. Restoration of the liver of the white rat following partial surgical removal. Arch Pathol. 1931;12:186–202 — first experimental model of liver regeneration (historical, no DOI).
3. British Museum. Clay model of a sheep’s liver, Babylon, ca. 1900–1600 BC (museum no. 1889,0426.238) — hepatoscopy; the liver as the “seat of life” (archaeological primary source).
4. Michalopoulos GK, Bhushan B. Liver regeneration: biological and pathological mechanisms and implications. Nat Rev Gastroenterol Hepatol. 2021;18(1):40–55. DOI — repair and the “hepatostat”.
5. Maiwall R, Kulkarni AV, Arab JP, Piano S. Acute liver failure. Lancet. 2024;404(10454):789–802. DOI — acute liver failure and transplantation.
6. Whitfield JB, et al. A genetic risk score and diabetes predict development of alcohol-related cirrhosis in drinkers. J Hepatol. 2022;76(2):275–282. DOI — why one person falls ill and another doesn’t.
7. Chen Y, et al. Genome-wide association meta-analysis identifies 17 loci associated with nonalcoholic fatty liver disease. Nat Genet. 2023;55(10):1640–1650. DOI — genetic predisposition to liver disease.
8. Kanwar P, Kowdley KV. Metal storage disorders: Wilson disease and hemochromatosis. Med Clin North Am. 2014;98(1):87–102. DOI — iron and copper accumulation.
9. Single-cell analysis of the amphioxus hepatic caecum and vertebrate liver reveals genetic mechanisms of vertebrate liver evolution. Nat Ecol Evol. 2024. DOI — evolutionary origin and step-by-step build-up.
10. Lips P. Hypervitaminosis A and Fractures (editorial). N Engl J Med. 2003;348(4):347–349. DOI — Gerrit de Veer’s diary (1597) and vitamin A.
11. De Veer G. The Three Voyages of William Barents to the Arctic Regions. Hakluyt Society — historical primary source (Project Gutenberg).
12. Monitoring the Future (University of Michigan) — long-running research into declining alcohol use among young people (trend, no single DOI; figures vary by country and year).
13. Marlboro Man — Leo Burnett advertising campaign (US, 1954–1999); a cultural example of an image of rugged masculinity that fully tipped over within a few decades (historical/cultural).