The Liver: What It Is and How It Functions
Published on February 5, 2025
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The liver, located in the upper right side of the abdomen, is the body’s largest organ and one of the most important. The liver performs hundreds of vital functions, including converting nutrients from food into energy, filtering toxins from the blood, and producing bile, a key substance in digestion and waste removal.
Here’s what to know about how the liver functions, the causes and symptoms of liver diseases, and what you can do to keep this essential organ healthy.
What Is the Liver?
“The liver is essential to our overall health in so many ways, including digestion, metabolism, and immune function,” says Wendi LeBrett, MD, a gastroenterologist in Boise, Idaho, who educates the public on liver health.
Functioning as both an organ and a gland, the liver filters harmful substances from your blood. It stores excess glucose (sugar) and releases it when needed to help control blood sugar. It excretes bile to break down fats and aid digestion. Your liver also stores, processes, and delivers nutrients to the rest of your body, keeping your energy levels steady throughout the day.
Where Is the Liver Located?
Your liver sits just under your lungs on the right side of your abdomen. As your body’s largest internal organ, it weighs between 3 and 5 pounds and dominates the space beneath your rib cage. The gallbladder is tucked into the hollow underneath, with the stomach, right kidney, and intestines right below.
What Does the Liver Do?
The liver processes everything that enters your body, from food to medications. Here are the functions your liver performs:
- Cleans toxins from the blood, including substances like alcohol and medications
- Regulates blood sugar by storing extra sugar (glucose) for later use when needed
- Supports digestion by producing bile to help break down fats
- Eliminates waste products such as bilirubin, a byproduct of the natural breakdown of red blood cells
- Regulates blood clotting, which prevents excessive bleeding
- Fights infections by removing bacteria from the bloodstream
- Stores vitamins and minerals, including vitamins A, D, E, K, and B12, as well as iron and copper
The Different Parts of the Liver
Key parts of the liver include:
- Lobes The liver consists of two main lobes, each of which is divided into eight segments.
- Hepatic Portal Vein Blood carrying nutrients, medications, or toxins from the digestive tract travels to the liver via the hepatic portal vein.
- Hepatic Artery This artery brings oxygen-rich blood to the liver from the heart.
- Hepatic Veins These veins drain blood blood back to the heart.
- Lobules These are hexagonal clusters of liver cells (hepatocytes) that produce bile.
- Common Hepatic Duct This carries bile to the gallbladder and intestines.
Conditions That Can Affect the Liver
Viruses, alcohol, obesity, medications, genetic conditions, and autoimmune disorders can all harm your liver. Here are some common liver conditions:
- Hepatitis Inflammation of the liver is most often caused by the hepatitis A, hepatitis B, and hepatitis C viruses. “These viruses can cause cell death, and chronic infections can lead to scarring, or fibrosis,” says Sudha Kodali, MD, a hepatologist in Sugar Land, Texas, and a volunteer for the American Liver Foundation. There are vaccines for hepatitis A and B. While there is no vaccine for hepatitis C, proper treatment can cure the virus in more than 95 percent of cases.
- Fibrosis Persistent inflammation creates scar tissue that restricts oxygen and nutrients. Liver cells can regenerate and scarring can diminish, making fibrosis reversible if detected early.
- Cirrhosis When excessive scar tissue forms, fibrosis becomes irreversible, leading to cirrhosis. Chronic liver diseases, hepatitis, and alcohol use can cause cirrhosis. Without treatment, cirrhosis leads to liver failure.
- Metabolic Dysfunction–Associated Steatotic Liver Disease (MASLD) Formerly known as nonalcoholic fatty liver disease (NALFD) MASLD occurs when fat builds up to more than 5 to 10 percent of your liver’s weight. MASLD is common in people who are overweight, obese, have diabetes, high cholesterol, or high triglycerides, and can progress to cirrhosis or the advanced stage of MASLD called metabolic dysfunction-associated steatohepatitis (MASH).
- Alcohol-Associated Liver Disease Includes several alcohol-influenced conditions, like fatty liver disease, hepatitis, and cirrhosis.
- Liver Cancer The most common type of liver cancer is hepatocellular carcinoma (HCC); HCC rarely develops without preexisting cirrhosis.
- End-Stage Liver Disease Also known as chronic liver failure, this is when the liver can no longer function adequately.
Symptoms of Liver Problems
Typically, people with liver disease don’t experience symptoms until the disease is advanced. While symptoms of liver disease vary, common symptoms include:
- Yellowing of the skin or eyes (jaundice)
- Unexplained bruising or blood clotting problems
- Swelling in the abdomen, ankles, or legs
- Abdominal pain
- Mental confusion
- Dark yellow or brown urine
- Clay-colored stool
- Low blood pressure
- Itchy skin
If you have any symptoms of liver problems, especially jaundice or abdominal pain, seek medical care immediately.
How to Keep Your Liver Healthy
“There are several factors that increase the risk of liver disease that are, for the most part, under your control,” says Dr. Kodali. Here’s how to help protect your liver:
Limit alcohol consumption. Nearly half of all liver disease deaths in America are related to alcohol use. Experts recommend that women of any age and men over 65 have no more than one drink per day; men under 65 should have no more than two drinks a day. (One drink equals 12 ounces of beer, 5 ounces of wine, or 1.5 ounces of spirits.) “The risk of liver damage increases with the amount of alcohol you consume,” says Kodali. Nearly all heavy drinkers develop MASLD and up to 20 percent develop cirrhosis. Fortunately, you can often reverse alcohol-related liver disease by stopping drinking.
Maintain a healthy weight. “Excess weight causes fat to accumulate in the liver, which can lead to inflammation and development of scar tissue,” explains Kodali. For people living with excess weight or obesity, losing just 10 percent of their body weight can reduce liver fat, calm inflammation, and even help heal scarring.
Move your body. Regular physical activity improves blood flow to the liver, decreases inflammation, and reduces liver fat. It also helps with weight loss. Research has found both aerobic and resistance exercise improved liver health in as little as 12 weeks, regardless of weight changes. More reason to move: Physically active people at risk for liver cancer may be up to 60 percent less likely to develop the disease. Regular activity also protects your heart — an important benefit since heart disease is the leading health risk for people with fatty liver.
Follow the Mediterranean diet. Dr. LeBrett recommends the Mediterranean diet, noting that it’s the best studied for people with fatty liver disease. Research has shown that a traditional Mediterranean diet reduced liver fat by about 20 percent, while an enhanced “green” Mediterranean diet reduced liver fat by 39 percent. The green version emphasized plant-based proteins, like frozen Mankai (an edible aquatic plant), placed stricter limits on red and processed meats, and added green tea to the mix.
Consider coffee. Drinking more than three cups of coffee daily may help reduce fibrosis, according to research. “The effects are likely due to the antioxidant content in coffee, so this holds true for decaf and instant coffee, too,” says LeBrett. Just be sure to avoid adding a lot of sugar and creamers to your coffee, as those can negate the overall health benefits.
Keep up with appointments and vaccines. Because liver disease is often silent, regular checkups are essential. “Some people only know something is wrong with their liver through abnormalities in their liver enzymes on routine blood tests,” says LeBrett. Ask your doctor if you’re up to date on your hepatitis A and B vaccines.
Be safe with supplements. “Several commonly used OTC supplements, including green tea extract, turmeric, and certain workout supplements, have been associated with liver injury or liver failure,” warns LeBrett. Those with underlying liver conditions should be particularly cautious. That said, there’s no need to panic: Complications are rare. In one study, researchers reported only 10 cases of serious liver injury from turmeric among millions of users over nearly two decades. Always inform your healthcare provider about any supplements you’re taking.
Use medications wisely. Even common over-the-counter pain relievers like acetaminophen can damage your liver if misused. Follow dosing instructions carefully.
The Takeaway
- Your liver performs hundreds of vital functions, including converting nutrients into energy, filtering toxins from the blood, and producing bile, an important substance for digestion.
- Simple lifestyle changes, such as staying physically active, avoiding alcohol, and eating a Mediterranean-style diet can help prevent and even reverse early liver disease.
- While alcohol is the leading cause of liver disease in America, about a quarter of Americans have fatty liver disease due to excess weight, making weight management crucial for liver health.
- If you notice symptoms like yellowing of the skin or eyes, constant itching, or severe abdominal pain, seek immediate medical attention.
Meet Our Experts
Allison Buttarazzi, MD
Medical Reviewer
Allison Buttarazzi, MD, is board-certified in internal medicine and lifestyle medicine, and is a certified health and well-being coach. In her primary care practice, Dr. Buttarazzi focuses on lifestyle medicine to help her patients improve their health and longevity, and her passion is helping patients prevent and reverse chronic diseases (like heart disease, high blood pressure, and diabetes) by improving their lifestyle habits.
She is a graduate of Tufts University School of Medicine and completed a residency at Maine Medical Center. Diagnosed with celiac disease during medical school, she realized the power of improving one's health through diet and lifestyle habits, which she later incorporated into her practice.
Holly Pevzner
Author
Holly Pevzner is a writer who specializes in health, nutrition, parenting, and pregnancy. She is currently a staff writer at Happiest Baby. Her work, including essays, columns, features, and more, spans a variety of publications, websites, and brands, such as EatingWell, Family Circle, Fisher-Price, Parents, Real Simple, and The Bump. Pevzner has written several monthly health columns, including for First for Women and Prevention magazines. She previously held senior staff positions at Prevention, Fitness, and Self magazines, covering medical health and psychology. She was also a contributing editor at Scholastic's Parent & Child magazine.
EDITORIAL SOURCES
Everyday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.
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