Gilbert’s syndrome is an inherited liver condition in which your liver can’t fully process a compound called bilirubin.

Your liver breaks down old red blood cells into compounds, including bilirubin, which are released in feces and urine. If you have Gilbert’s syndrome, bilirubin builds up in your blood stream, causing a condition called hyperbilirubinemia. You might see this term pop up in the results of a blood test. It simply means you have high levels of bilirubin in your body. In many cases, high bilirubin is a sign that there’s something going on with your liver function. However, in Gilbert’s syndrome, your liver is typically otherwise normal.

About of people in the United States have Gilbert’s syndrome. Some studies show it may be as high as . It isn’t a harmful condition and doesn’t need to be treated, though it can cause some minor problems.

Gilbert’s syndrome doesn’t always cause noticeable symptoms. In fact, of people with Gilbert’s syndrome may never have any symptoms. Some people with Gilbert’s syndrome never even know they have it. Often, it’s not diagnosed until early adulthood.

When it does cause symptoms, these can include:

If you have Gilbert’s syndrome, you might notice these symptoms more if you do things that can further increase your bilirubin levels, such as:

  • experiencing emotional or physical stress
  • exercising vigorously
  • not eating for a long period of time
  • not drinking enough water
  • not sleeping enough
  • being sick or having an infection
  • recovering from surgery
  • menstruating
  • cold exposure

Some people with Gilbert’s syndrome also find that drinking alcohol makes their symptoms worse. For some people, even one or two drinks can make them feel sick shortly after. You might also have what feels like a hangover for several days. Alcohol can temporarily raise bilirubin levels in people with Gilbert’s syndrome.

Gilbert’s syndrome is a genetic condition that’s passed down from your parents.

It’s caused by a mutation in the UGT1A1 gene. This mutation results in your body creating less bilirubin-UGT, an enzyme that breaks down bilirubin. Without proper amounts of this enzyme, your body can’t process bilirubin correctly.

Your doctor may test you for Gilbert’s syndrome if they notice jaundice without other signs or symptoms of a liver problem. Even if you don’t have jaundice your doctor may notice higher levels of bilirubin during a routine liver function blood test.

Your doctor may also conduct tests such as a liver biopsy, CT scan, ultrasound, or other blood tests to rule out any other medical conditions that could be causing or adding to your abnormal bilirubin levels. Gilbert’s syndrome can occur alongside other liver and blood conditions.

You’ll likely be diagnosed with Gilbert’s syndrome if your liver tests show increased bilirubin and there is no other evidence of liver disease. In some cases, your doctor might also use a genetic test to check for the gene mutation responsible for the condition. The medications niacin and rifampin can cause a rise in bilirubin in Gilbert’s syndrome and also lead to a diagnosis.

Most cases of Gilbert’s syndrome don’t require treatment. However, if you start to have significant symptoms, including fatigue or nausea, your doctor might prescribe daily phenobarbital (Luminal) to help reduce the total amount of bilirubin in your body.

There are also several lifestyle changes you can make to help prevent symptoms, including:

  • Get plenty of sleep. Try to sleep seven to eight hours a night. Follow a consistent routine as closely as you can.
  • Avoid long periods of intense exercise. Keep strenuous workouts short (under 10 minutes). Try to get at least 30 minutes of light to moderate exercise each day.
  • Stay well hydrated. This is especially important during exercise, hot weather, and illness.
  • Try relaxation techniques to cope with stress. Listen to music, meditate, do yoga, or try other activities that help you relax.
  • Eat a balanced diet. Eat regularly, don’t skip any meals, and don’t follow any diet plans that recommend fasting or eating only small amounts of calories.
  • Limit alcohol intake. If you have any liver condition, it’s best to avoid alcohol. However, if you do drink, consider limiting yourself to only a few drinks per month.
  • Learn how your medications interact with Gilbert’s syndrome. Some medications, including some used to treat cancer, may work differently if you have Gilbert’s syndrome.

Gilbert’s syndrome is a harmless condition that doesn’t need to be treated. There is no change in life expectancy due to Gilbert’s syndrome. However, if you start to notice symptoms, you may need to make some lifestyle changes.