What causes diarrhea after drinking alcohol?

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Alcohol is easy for body tissues to absorb. As soon as alcohol enters the body, it starts making its way into the bloodstream. Some of this absorption happens in the stomach.

If there is food in the stomach at the time, the absorption rate will slow. This is why people feel the effects of alcohol more quickly on an empty stomach.

Once alcohol leaves the stomach, the small intestine starts to absorb it. Much of the alcohol is absorbed here, but the remainder goes into the large intestine and exits with the stool and urine.

Alcohol can affect the normal functions of the digestive system at every stage.

These changes include:

• Inflammation: Contact with alcohol can cause the gastrointestinal tract to become inflamed. Alcohol can also lead to more acid production in the stomach, which can increase irritation and inflammation. This irritation can lead to diarrhea.
• Water absorption: Water is usually absorbed from the foods and liquids reaching the intestines. The large intestine pulls liquids out of the stool before passing it out of the body. When alcohol is present, the large intestine does not function as well. This can result in liquid stools and dehydration.
• Faster digestion: Alcohol agitates the intestines and causes them to react by speeding up digestion. The muscles in the colon contract more frequently, pushing stool out faster than usual. This quickening can lead to diarrhea, as the intestines do not have time to digest the passing food properly.
• Bacterial imbalance: A variety of bacteria in the intestines work to keep the body in balance by attacking harmful pathogens. Alcohol may temporarily kill off some bacteria species or allow others to grow rapidly, which can cause the intestines to malfunction.

Certain factors can affect the risk and severity of diarrhea after drinking alcohol.

Lifestyle choices

Some lifestyle factors that may increase the risk include:

• having alcohol use disorder, which can affect the whole intestinal tract and may result in diarrhea
• having several alcoholic drinks in quick succession, sometimes called binge drinking
• eating heavy foods while drinking

The body has trouble digesting food when alcohol is working its way through the intestinal tissues, and alcohol may reduce the digestive enzymes necessary to break down heavy food.

Some research suggests a lack of sleep may also contribute, as changes to the body clock may disrupt intestinal function.

Other gastrointestinal conditions

A person is more likely to have diarrhea, and to have it more severely, if they have certain health conditions, such as:

• irritable bowel syndrome (IBS)
• celiac disease
• Crohn’s disease

People with a gluten intolerance may have a reaction to the grains in beer and certain liquors. Anyone with a more sensitive digestive tract, in general, may also be more sensitive to the effects of alcohol.

Certain alcoholic beverages may cause more symptoms than others, although alcoholic drinks can affect individuals differently.

• Beer has more carbohydrates compared to other forms of alcohol. The body can have trouble breaking down these extra carbs while drinking alcohol. This can lead to diarrhea.
• Wine is more likely to cause diarrhea in some people. This may be due to a sensitivity or allergy to tannins. Tannins are compounds found in the skin of grapes, and a reaction may lead to headaches, nausea, and diarrhea.
• Mixed drinks can be high in sugar. This can worsen diarrhea in some people. Excess sugar causes the body to push out the contents of the intestines quicker.

Here are some tips for preventing diarrhea due to alcohol consumption:

• Be mindful of drinking habits, including how much you drink and how often.
• Drink slowly to ease stress on the digestive tract.
• Consume a non-alcoholic drink, such as water, between each alcoholic beverage.
• Replace drinks that cause gastrointestinal symptoms with a different type of alcohol.
• Eat before drinking to slow the absorption of alcohol into the body and reduce the risk of diarrhea.
• Avoid alcoholic beverages mixed with caffeine, as caffeine can increase movement in the intestine and the speed of digestion.

The Centers for Disease Control and Prevention (CDC) recommend that females consume no more than 1 drink per day and males 2 drinks or less per day.

Diarrhea after one night of drinking may last a few days if the drinking has ceased, but a lot depends on how sensitive one’s gut is to alcohol and whether the drinking continues.

A person who regularly consumes large amounts of alcohol may have intestinal changes that cause persistent diarrhea.

During recovery:

• Eat bland, easily-digested foods such as rice, toast, or plain crackers, as these can help fill the stomach without causing additional symptoms.
• Avoid dairy products and foods high in fat or fiber immediately after diarrhea to help reduce stress on the digestive system while it is trying to recover.
• Drink water or herbal teas to help replace fluids lost through urine and diarrhea and prevent dehydration.

If diarrhea persists, over-the-counter medications can help the body soak up water and fill out the stool.

Probiotics may also balance gut bacteria.

Persistent diarrhea may be a sign of a separate condition that may require a doctor’s visit. A person may also need medical attention if they become severely dehydrated.

A doctor should be notified if the following symptoms occur:

• persistent diarrhea lasting more than 2 days
• dry mouth and continuous thirst
• low or no urine, even with extra fluid intake
• infrequent urine that is often very dark in color
• weakness and fatigue
• dizziness or lightheadedness
• fever
• intense cramps and pain
• bloody stool
• black stool that is not caused by an antidiarrheal medication

Dehydration can be life-threatening, so anyone experiencing the above symptoms should contact a doctor.

You may also wish to consider seeing a doctor if you have concerns about how alcohol is affecting you. The National Institute on Alcohol Abuse and Alcoholism (NIAAA)’s treatment navigator can help people find the correct type of help.

How does alcohol cause diarrhea?

One way alcohol can increase the risk of diarrhea is by agitating or irritating the intestinal tract and speeding up digestion. As the muscles in the colon contract more frequently, they push stool out faster, which may lead to diarrhea.

Certain health conditions and a high, regular alcohol intake can cause sensitivity in the gut, which may also increase the risk.

How long does diarrhea last after alcohol?

Diarrhea after alcohol usually lasts a few days, but it can come back if a person consumes more alcohol. People who regularly consume a lot of alcohol may have persistent diarrhea due to damage in the gastrointestinal tract.

Some people experience diarrhea after consuming alcohol, especially if they consume a large amount, if they have several drinks in quick succession, or if they have a sensitivity to alcohol or other ingredients in a drink.

In most cases of diarrhea caused by drinking, the symptoms will go away once the person returns to a normal diet and stops drinking alcohol.