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Your liver performs hundreds of important functions — from aiding absorption of food to removing toxic substances from your body. Normally, an adult liver is about the size of a small football. Sometimes, however, the liver becomes enlarged. This is known as hepatomegaly.

An enlarged liver isn't a disease. It's a sign of an underlying problem, such as hepatitis, congestive heart failure or cancer.

Treatment of an enlarged liver depends on the cause.

An enlarged liver usually causes no signs or symptoms.

If the liver enlarges quickly, it may be tender to the touch. A markedly enlarged liver may cause abdominal pain or fullness. If the cause of enlargement affects liver function, it may lead to yellowing of the skin (jaundice).

Many conditions may cause an enlarged liver, including:

• Alcohol abuse
• Nonalcoholic fatty liver disease
• Hepatitis
• Heart failure
• Liver cancer
• Infections such as mononucleosis
• Excessive iron in the body (hemochromatosis)
• Blood disorders such as leukemia

Each underlying problem has a distinct set of risk factors. For example:

• Alcohol abuse. Men are more likely to abuse alcohol than women are. The risk of alcoholism is higher if you have a family history of the disease. Depression and anxiety also increase the risk of alcohol abuse.
• Nonalcoholic fatty liver disease. Being overweight or obese is a major risk factor for nonalcoholic fatty liver disease. Having diabetes or abnormal cholesterol levels also increases the risk.
• Hepatitis A. You're at increased risk of hepatitis A if you travel or work in regions with high rates of hepatitis A; you're a sexually active gay or bisexual man; you use illicit drugs; you work in a research setting where you may be exposed to the virus; or you have hemophilia or receive clotting-factor concentrates for another medical condition.
• Hepatitis B. You're at increased risk of hepatitis B if you have unprotected sex with more than one partner; you have a sexually transmitted disease; you share needles during intravenous drug use; you live with someone who has a chronic hepatitis B infection; you have a job that exposes you to human blood; or you received a blood transfusion or blood products before 1970.
• Hepatitis C. You're at increased risk of hepatitis C if you inject or snort illicit drugs; you received an organ transplant before 1992; you've been exposed to infected blood; you received clotting factor concentrates before 1987; you have hemophilia and received blood products before 1992; or you're receiving hemodialysis for kidney failure.
• Heart failure. Various factors increase the risk of heart failure, including high blood pressure, coronary artery disease, diabetes, kidney failure and congenital heart defects.
• Liver cancer. Chronic infection with hepatitis B or C is the most important risk factor for liver cancer. Cirrhosis, diabetes, smoking and excessive alcohol consumption may increase risk as well.

Consult your doctor if you notice abdominal pain or fullness, swelling in your abdomen or yellowing of the skin.

Most cases of enlarged liver are detected during a physical exam. The doctor can estimate the size of your liver by feeling how far it extends below your rib cage. He or she will consider the texture of your liver as well. Depending on the underlying cause, an enlarged liver may feel soft, firm or irregular. Sometimes lumps are present as well.

Your doctor may recommend various diagnostic tests to help determine what's causing the enlarged liver, including:

• X-ray of the abdomen
• Ultrasound of the liver
• Computed tomography (CT) scan of the abdomen
• Blood tests of liver function
• Liver biopsy

Treatment of an enlarged liver depends on the cause.

• Alcohol abuse. If the enlarged liver is alcohol-related, it's essential to stop drinking. Although liver damage from cirrhosis is irreversible, treatment can often help prevent further damage and reduce complications.
• Nonalcoholic fatty liver disease. Weight loss and exercise are often an essential part of treatment. It's also important to avoid alcohol and keep your cholesterol under control. If you have diabetes, manage your blood sugar carefully.
• Hepatitis. There's no specific treatment for hepatitis A. Medication may be recommended for hepatitis B or C. If your liver has been severely damaged, a liver transplant may be an option.
• Heart failure. Various medications are used to treat heart failure. Some take the burden of extra fluid off the liver.
• Liver cancer. Depending on the type and stage of the disease and various other factors, liver cancer may be treated with surgery, radiation therapy or chemotherapy.
• Blood disorders. With hemochromatosis, regularly drawing blood can reduce the amount of iron the liver has to process. Treatment for leukemia is complex. Therapies may include chemotherapy and radiation.

To protect your liver, take good care of yourself.

• Drink alcohol in moderation, if at all. Too much alcohol can lead to fat accumulation, inflammation and scarring in the liver. If drinking continues, liver damage may be fatal.
• Don't mix alcohol with other drugs. Acetaminophen (Tylenol, others) can be toxic to the liver even if you drink in moderation.
• Use medications wisely. Take medication only when you need it. Limit yourself to the recommended doses. Talk to your doctor before mixing herbal supplements with prescription or nonprescription medications.
• Be cautious with supplements. Some supplements can damage the liver, including kava, comfrey, chaparral and pennyroyal. Avoid high doses of vitamins A, D, E and K.
• Reduce the risk of hepatitis. Avoid contact with other people's blood and body fluids. If you're at risk of contracting hepatitis A or B, ask your doctor about immunization.
• Limit contact with toxins. Use aerosol cleaners, insecticides and other toxic chemicals only in well ventilated areas. Better yet, wear gloves, long sleeves and a mask.
• Make good choices about diet and exercise. Eating healthy foods and exercising regularly can help you control your weight — and help your liver do its job.