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How the Human Body Processes Alcohol


serving beer to customers



How does your body absorb alcohol? Get answers to questions about why different alcohols get absorbed differently and how your body gets rid of alcohol.

Alcohol Absorbtion

Why does alcohol get into the bloodstream so quickly?

Alcohol is absorbed very quickly by the blood and spreads easily to all organs because alcohol molecules are very tiny. They don’t have to be broken down by digestive enzymes to get into the blood and they dissolve easily in water and fat – both main components of the human body.

Why is alcohol absorbed more quickly when the stomach is empty?

Alcohol moves quickly from the mouth to the stomach and on to the intestines. Some of it is absorbed directly through the lining of the mouth and esophagus, some through the walls of the stomach and the rest is absorbed by the intestines, mainly the small intestine.

If there is no solid food in the stomach or intestines, the alcohol will come into contact with the intestinal walls more easily and pass quickly into the blood. All the alcohol of one drink may be absorbed within 30 minutes.

If your stomach is relatively full, the alcohol will stay there longer. The absorption process will be slower and may take up to 90 minutes.

Why is stronger alcohol absorbed more slowly?

Beverages that are more than 20 per cent alcohol irritate the lining of the stomach. This slows the opening of the valve that allows the contents of the stomach pass into the small intestine. Drinking several shots of spirits one after the other in the hope of getting drunk quickly may actually produce a delayed reaction.

Why does alcohol go to your head so quickly?

Once it’s in the bloodstream, alcohol spreads to all parts of the body and goes into all tissues containing water. Because alcohol is carried by blood, it is delivered particularly quickly to organs with many blood vessels, such as the brain, lungs and liver.


Alcohol Elimination

Why is there alcohol in the breath you exhale and in breast milk?

About 10 per cent of alcohol is eliminated as is, through urine or perspiration. It can also be eliminated through the breath, since the bloodstream carries it to the lungs. This is why a breathalyzer can measure your blood alcohol level.

Did you know?
The concentration of alcohol in breast milk is about 10 per cent higher than in the blood because of the high water content of the milk.

How is alcohol metabolized by the liver?

About 90 per cent of alcohol is eliminated by the body’s metabolism. While the kidneys and gastro-intestinal tract play a role in this process, the liver is the main organ responsible for transforming alcohol absorbed by the blood into substances that your body can process and eliminate.

Why do different people eliminate alcohol differently?

No matter how much or how little you drink, your liver can only metabolize about one standard drink per hour. Other factors include age, gender, weight and how much food you’ve had to eat.

© Adapted from Éduc’alcool’s “Alcohol and Health” series, 2014. Used under license.
Last Updated: August 26, 2019