How long it takes the liver to process alcohol can vary. On average, the liver can process 1 ounce of alcohol every hour. It may be possible to detect it in the blood for several hours, and in the urine for several days.

The following is information on how the body processes alcohol and the different factors that can affect that process.

Fast facts on how long alcohol stays in your system:

  • Alcohol enters the bloodstream through the stomach.
  • In general, the liver can process up to an ounce of alcohol every hour.
  • The effects of alcohol come from its presence in the blood and body tissues.
  • Alcohol can be detected in the blood, urine and even on the breath.
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The effects of a high blood alcohol concentration may include impaired memory, confusion, slurred speech, and nausea.Share on Pinterest
The effects of a high blood alcohol concentration may include impaired memory, confusion, slurred speech, and nausea.

Around 20 percent of the alcohol a person drinks is absorbed rapidly into the bloodstream through the stomach. A further 80 percent approximately is absorbed by the small intestines.

Any remainder that is not metabolized leaves the body through sweat, urine, and saliva.

Once alcohol reaches the bloodstream, it goes to the liver to be processed or metabolized. The liver produces enzymes that break down the alcohol molecules.

When someone is drinking alcohol particularly quickly, the liver cannot process all the alcohol at the same rate, so it remains in the body.

The higher a person’s blood alcohol concentration (BAC) is, the more pronounced the effects are. These effects may include:

  • reduced inhibitions
  • impaired memory
  • slurred speech
  • confusion
  • difficulty concentrating
  • breathing problems
  • nausea or vomiting
  • impaired balance and coordination
  • irritability

There are many factors that can affect how alcohol is processed by the body.


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Blood flow may be slower in older people, so alcohol may stay in the system for longer.

Alcohol stays in the liver longer the older a person is.

Blood flow may be slower, and an older person may be more likely to be taking medication that affects the liver.

These factors mean that alcohol is processed at a slower rate, which can increase the amount of alcohol absorbed into the body.


Though not true for everyone, alcohol tends to stay in a woman’s system for longer than a man’s. This is because women tend to have a higher percentage of body fat and a lower percentage of body water than men.


Because alcohol is absorbed into the digestive tract, the presence of food in the stomach has a significant effect on the absorption rate of alcohol. Having a full stomach can slow down absorption dramatically.


Some people of East Asian descent lack the enzymes necessary to break down alcohol. This can cause a reaction that includes facial flushing, nausea, dizziness, rapid heart rate, and headache.

Family history

Research has shown that alcohol use disorder, or alcoholism, tends to run in families, suggesting a genetic link. However, genes alone are not responsible for whether someone becomes an alcoholic.

Studies have shown that both genetic and environmental factors can affect how the body processes and deals with alcohol.

Body size

Like other drugs and medications, a person’s body size can impact how alcohol is processed.

A person who is a lighter weight or who has a smaller body frame will be more affected than someone who weighs more or has a larger body frame.

Time since the last drink

The liver is more able to process the next drink the longer it has been since the previous one.

Someone who is quickly drinking one alcoholic drink after another is more likely to experience stronger effects in a shorter amount of time.


Certain medications can affect how the body is able to process alcohol. Medications that are specifically known to interact with alcohol include:

How long alcohol is detected in the system depends on what is being tested.


The concentration of alcohol in the blood, or BAC, helps to determine how long alcohol stays in the system.

In general, alcohol is eliminated at 0.015 per hour. For example, someone who has a BAC Of 0.08, which is when it becomes illegal to drive, will take around 5.5 hours to flush the alcohol out of their body.

It is important to know that someone who drinks a lot or on an empty stomach may still have alcohol in their system the next day, making it illegal to drive a vehicle even then.


How long alcohol is detectable in the urine will depend on the test used, as some urine tests are far more sensitive than others.

Currently, there is a test that can detect alcohol use up to 80 hours, or 3 to 4 days, after the last drink a person had.


Frequently checked as part of routine breathalyzer testing, alcohol can be detected in the breath for up to 24 hours after the last drink.


Hair testing can be used to detect the use of many different substances, including alcohol. Alcohol can be detected in the hair for around 90 days after an alcoholic drink was consumed.

Breast milk

Alcohol can remain in the breast milk for as long as it remains in the blood. As alcohol leaves the blood, it also leaves the milk, making it unnecessary to “pump and dump” breast milk after drinking alcohol.

Pumping breast milk will not eliminate alcohol from the milk any quicker.


Trace amounts of alcohol can be detected in a saliva swab around 10-24 hours after the last drink.

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The long-term risks of heavy drinking may include liver disease, heart disease, and stroke.

While alcohol use is commonplace, there are health risks associated with heavy drinking. Heavy alcohol use is linked with:

Keeping track of what and how much a person drinks can help them recognize when they might be drinking too much.

For many people, drinking alcohol is a part of life. For example, having a beer during a baseball game or a glass of wine with dinner is commonplace.

However, regular use of alcohol is not without risk, and the alcohol can remain in the system for quite a while, depending on several factors.

Someone who feels that they are drinking too much or is having difficulty cutting back should speak with their doctor for advice on quitting.