Gilbert (zheel-BAYR) syndrome is a common, harmless liver condition in which the liver doesn't properly process bilirubin. Bilirubin is produced by the breakdown of red blood cells.

The liver

The liver

The liver is your largest internal organ. About the size of a football, it's located mainly in the upper right portion of your abdomen, beneath the diaphragm and above your stomach.

Gilbert syndrome is an inherited genetic condition. You might not know you have Gilbert syndrome until it's discovered by accident, such as when a blood test shows raised bilirubin levels.

Gilbert syndrome requires no treatment.


The most frequent sign of Gilbert syndrome is an occasional yellowish tinge of the skin and the whites of the eyes as a result of slightly higher levels of bilirubin in the blood. In people with Gilbert syndrome, bilirubin levels may increase due to:

  • Illness, such as a cold or the flu
  • Fasting or eating a very low-calorie diet
  • Dehydration
  • Menstruation
  • Strenuous exercise
  • Stress

When to see a doctor

Make an appointment with your health care provider if you have jaundice, which has many possible causes.


Gilbert syndrome is caused by a modified gene you inherit from your parents. This gene usually controls an enzyme that helps break down bilirubin in your liver. When you have an ineffective gene, your blood contains excess amounts of bilirubin because your body doesn't produce enough of the enzyme.

How the body processes bilirubin

Bilirubin is a yellowish pigment made when your body breaks down old red blood cells. Bilirubin travels through your bloodstream to the liver, where the enzyme breaks down the pigment and removes it from the bloodstream.

The bilirubin passes from the liver into the intestines with bile. It's then excreted in stool. A small amount of bilirubin remains in the blood.

How the modified gene is passed through families

The modified gene that causes Gilbert syndrome is common. Many people carry one copy of this gene. In most cases, two modified copies are needed to cause Gilbert syndrome.

Risk factors

Although it's present from birth, Gilbert syndrome usually isn't noticed until puberty or later, since bilirubin production increases during puberty. You have an increased risk of Gilbert syndrome if:

  • Both your parents carry the modified gene that causes the disorder
  • You're male


The low level of the bilirubin-processing enzyme that causes Gilbert syndrome may also increase the side effects of certain medications, since this enzyme plays a role in helping clear these medications from your body.

These medications include:

  • Irinotecan (Camptosar), a cancer chemotherapy drug
  • Some protease inhibitors used to treat human immunodeficiency virus (HIV)

If you have Gilbert syndrome, talk to your health care provider before taking new medications. Also, having any other condition that impairs the destruction of red blood cells may increase your risk of developing gallstones.

Jul 01, 2022

  1. Feldman M, et al., eds. Jaundice. In: Sleisenger and Fordtran's Gastrointestinal and Liver Disease: Pathophysiology, Diagnosis, Management. 11th ed. Elsevier; 2021. https://www.clinicalkey.com. Accessed June 1, 2022.
  2. Ferri FF. Gilbert syndrome. In: Ferri's Clinical Advisor 2023. Elsevier; 2023. https://www.clinicalkey.com. Accessed June 1, 2022.
  3. Gilbert syndrome. American Liver Foundation. https://liverfoundation.org/for-patients/about-the-liver/diseases-of-the-liver/gilbert-syndrome/. Accessed May 31, 2022.
  4. Chowdhury JR, et al. Gilbert's syndrome and unconjugated hyperbilirubinemia due to bilirubin overproduction. https://www.uptodate.com/contents/search. Accessed June 1, 2022.


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