When you drink alcohol, you don’t digest alcohol. It passes quickly into your bloodstream and travels to every part of your body. Alcohol affects your brain first, then your kidneys, lungs and liver. The effect on your body depends on your age, gender, weight and the type of alcohol.
Your bloodstream distributes alcohol quickly to your brain, kidney, lungs and liver. On average, your liver takes an hour to break down one unit of alcohol. This can depend on:
- your weight
- your gender
- your age
- how quickly your body turns food into energy
- how much food you’ve eaten
- the strength and type of alcohol
- any medicine you’re taking
Weight
If your weight is low, you feel the effects of alcohol more quickly because you have less tissue to absorb alcohol.
Age
Most children and young people are smaller and weigh less than adults. Alcohol can affect them quickly. Children and young people’s brains are still developing, so even small amounts of alcohol can be damaging.
Your body changes as you reach old age. You have increased body fat and decreased body water. This affects how your body processes alcohol. If you still drink the same amount of alcohol you drank in adulthood, you feel the effects more severely. Older people who drink too much alcohol are at greater risk of physical and mental health problems including:
- stroke
- heart disease
- cancer
- depression
- confusion
- dementia
Gender
Alcohol affects women more quickly than men. Women are usually smaller and weigh less than men, and have less tissue to absorb alcohol.
A woman’s body has more fat and less water than a man’s body. If a man and woman are the same size and drink the same amount, the alcohol is stronger in the woman's blood than in the man’s. The woman will get drunk more quickly and feel the effects for longer.
Alcohol also stays in women’s blood for longer. They have lower levels of the enzyme that breaks down alcohol.
Women feel the effects of alcohol more quickly before a period and during ovulation. The contraceptive pill can have the opposite effect – it takes longer for alcohol to leave the body. A woman in this situation might drink more than she realises before she feels the effects.
Stomach
You absorb 20 per cent of alcohol into your bloodstream through your stomach and the rest into your bloodstream through your small intestine.
Drinking a small amount of alcohol stimulates your appetite because it increases the flow of stomach juices. A large amount of alcohol dulls your appetite and can cause malnutrition.
You can develop a stomach ulcer by drinking too much alcohol. This can happen when the stimulated gastric juices mix with the high alcohol content and irritate your stomach lining.
Bloodstream
When alcohol enters your bloodstream, it widens your blood vessels. This causes:
- blushing, as there is a greater flow of blood to the skin surface
- a temporary feeling of warmth
- heat loss and a rapid decrease in body temperature
- a drop in blood pressure
Brain
Alcohol dulls the parts of your brain that control how your body works. This affects your actions and your ability to make decisions and stay in control. Alcohol influences your mood and can also make you feel down or aggressive.
As the concentration of alcohol in your bloodstream increases, your behaviour and body functions change. At first, you may feel happy and less inhibited, but after several drinks you'll probably:
- slur your words
- have blurred vision
- lose your coordination
There is no immediate way to sober up. It takes time for your body to process alcohol. The morning after a heavy night’s drinking, you are likely to have a high concentration of alcohol in your bloodstream.
You may not be sober or safe to drive a vehicle. The legal alcohol limit for driving measures the amount of alcohol in your breath, blood or urine.
Kidneys
Alcohol is a diuretic and increases urine production. When you drink alcohol, you need to urinate more often. This causes thirst and dehydration.
Lungs
When alcohol is fizzy, you can inhale this. From your lungs, alcohol goes quickly into your bloodstream.
Liver
When you drink alcohol, your liver oxidises 95 per cent of it. This means your liver converts alcohol into water and carbon monoxide. Your liver can only oxidise one unit of alcohol an hour.
Drinking with an empty or full stomach
If you drink alcohol with an empty stomach, the alcohol passes directly into your bloodstream. If you’ve eaten before drinking, the rate of alcohol absorption slows down but doesn’t stop.
Types of drink
Alcohol mixed with water or fruit juice is absorbed more slowly. Alcohol mixed with fizzy drinks or mixers is absorbed more quickly.
More useful links
Alcohol has many different effects on the body, both short- and long-term. It can affect how the body breaks down nutrients, irritate the gut, and speed up the digestive system. All of these effects can lead to a bowel movement.
Some alcoholic drinks have more of an effect on the body than others. The more a person drinks, the more likely they are to experience such effects. Eating a meal before drinking alcohol and drinking in moderation can help protect the gut and allow more regular, healthier bowel movements.
In this article, we explain how alcohol may affect the bowels, how to prevent these effects, and how to promote regular bowel movements.
Share on PinterestDrinking alcohol can speed up the digestive system, leading to a bowel movement.
Alcohol can cause serious changes in the function of the digestive system. It can overwhelm the gastrointestinal tract and cause intestinal inflammation.
Alcohol may make the digestive system work more quickly than usual. As the contents of the stomach will pass through the small and large intestines faster, the body may be unable to absorb the normal amount of water back into the body. This lack of reabsorption can result in a loose, watery stool.
As the digestive system is working faster than normal, it can make the need to poop urgent. A person may experience diarrhea after drinking alcohol.
Learn more about diarrhea after drinking alcohol.
Alcohol can also cause constipation because it is a diuretic. A diuretic is anything that causes the body to make more urine than normal. This effect can lead to dehydration because a person is urinating more often but not taking in enough fluids.
If a person experiences dehydration, their large intestine will take as much water as possible from waste before it leaves the body. This reabsorption can cause a hard, dry stool that is difficult to pass.
Alcohol irritates the gut, causing inflammation in the lining of the intestines, which stops the gut from absorbing nutrients as well as usual. Anything that the body cannot absorb will pass through the gut and out of the body as waste.
Therefore, the body may produce more waste than normal after a person drinks alcohol, and this may cause them to have more frequent bowel movements.
These problems can be worse if a person has gut problems, such as irritable bowel syndrome (IBS). In some cases, a person may be intolerant to some or all types of alcohol. Gluten in beer or tannins in wine can irritate the stomach.
Every person’s digestive system is different. People who drink regularly or in large amounts can find that alcohol irritates their stomach lining over time. These individuals may experience more frequent gut problems.
One of the most effective ways to limit the effects of alcohol is to drink in moderation. Most people should be able to avoid alcohol affecting their bowel movements if they limit their intake.
The Centers for Disease Control and Prevention (CDC) recommend safe limits for alcohol intake. For females, this is up to one drink per day. For males, it is up to two drinks per day.
The National Institute on Alcohol Abuse and Alcoholism consider one standard drink as:
- 12 ounces (oz) of 5% beer
- 8–9 oz of 7% malt liquor
- 5 oz of 12% red wine
- 1.5 oz of 40% spirits
People can keep track of which alcoholic drinks have the worst effect on their body and either replace these with an alternative or limit their consumption.
It may also be advisable to avoid mixing alcohol and drinks containing caffeine, such as energy drinks and coffee. Caffeine can irritate the stomach, speed up the digestive system, and possibly cause people to poop more often.
People should ensure that they stay hydrated by drinking plenty of fluids before drinking alcohol. Alternating each alcoholic drink with a soft drink and drinking water throughout the evening can help prevent dehydration and, in turn, help avoid constipation the next day.
Learn more about the risks of chronic heavy drinking.
To limit the effect of alcohol on the stomach and gut, it is advisable to eat beforehand rather than drinking alcohol on an empty stomach. Food can slow the absorption of alcohol and inhibit it coming into contact with the stomach lining.
The best foods to choose are plain, filling, and full of fiber. Foods to avoid include spicy, acidic, or fried foods, as these may irritate the stomach when people combine them with alcohol. Having enough food in the stomach can help limit some of the effects of alcohol on the body.
Some possible options include:
- bananas
- potatoes or sweet potatoes
- avocado
- legumes, such as pinto beans
- buckwheat
- freekeh
It is important to drink enough fluids to keep the stool soft and easy to pass. People can also try to poop at the same time each day to establish a regular schedule for bowel movements. However, they should not strain to force a bowel movement.
Learn more about how often people should poop.
Diarrhea after drinking should not last for longer than 48 hours. Once the body metabolizes alcohol, it should not continue to affect the body.
If diarrhea lasts longer than 48 hours, it can cause dehydration and other potential health problems. A person may wish to seek medical advice and treatment. They might need an oral rehydration solution to replace lost salts and electrolytes.
For constipation, a person should drink plenty of water, eat high fiber foods, and engage in physical exercise. If constipation is persistent, a pharmacist can usually recommend a mild laxative.
It is important to see a doctor if there is dark blood in the stool or bright red blood that continues to appear over a couple of days. These signs could indicate a more serious medical problem.
A person may wish to seek advice from a doctor if alcohol is adversely affecting their life. Signs of a potential problem with alcohol include drinking more than intended, risk-taking behavior, and being unable to cut down on alcohol.
Alcohol can irritate the digestive system and change how the body absorbs fluids. It may change the regularity of a person’s bowel movements and could result in either diarrhea or constipation.
Drinking too much alcohol can damage the stomach and gut over time. Limiting alcohol intake, eating before drinking alcohol, and staying hydrated can prevent problems the day after drinking.