Diarrhoea is a common condition that causes loose and watery stools, mostly in people with food poisoning. One possible cause of diarrhoea is the consumption of alcohol. Diarrhoea after drinking alcohol is a common phenomenon and is often referred to as "drunken diarrhoea." 

There are several reasons why this may occur. One reason is that you may be lactose-intolerant, causing the dairy-based alcoholic drinks to irritate the lining of the stomach and intestines, resulting in inflammation and increased production of stomach acid, leading to diarrhoea.⁸ Additionally, alcohol tends to act as a diuretic, causing an increase in urine production and a decrease in fluid in the body, leading to dehydration and possibly to diarrhoea.

This article will explore why you may experience diarrhoea after drinking alcohol and strategies for managing and treating it. We will also discuss when to call a doctor for further advice and treatment.

Overview

Diarrhoea is characterised by an increase in the water content of stools due to an imbalance in the physiological functions of the small and large intestines, which absorb various minerals, other nutrients, and, ultimately, water.¹

Based on the frequency and type of symptoms, diarrhoea is divided into acute or chronic. Diarrhoea is also classified as a non-infectious or infectious disease, depending on the cause. 

• Acute diarrhoea: An episode of acute diarrhoea lasts less than two weeks. A viral or bacterial infection most frequently causes acute diarrhoea. A viral infection causes the majority of instances and is self-limiting – that is, it typically resolves on its own without medication
• Chronic diarrhoea: Diarrhoea that lasts more than two weeks is referred to as chronic diarrhoea and is typically not contagious. Malabsorption (poor absorption of nutrients), inflammatory bowel illness, and drug interaction or side effects are common causes

The tell-tale characteristic of diarrhoea is a loose or watery stool and frequent visits to the bathroom, which may be accompanied by other symptoms, including:¹

• Nausea or vomiting
• Abdominal pain
• Fever
• Bloating
• Mucus in stool

Why do I get diarrhoea after drinking alcohol?

Not only can alcohol affect your brain and maybe your mood, but it also affects your digestive system. The type, duration, and quantity of alcohol you take also play a role in how much your stomach and intestines are affected.²

People who have stomach conditions, such as irritable bowel syndrome, coeliac disease, and Crohn's disease, have a higher risk of getting diarrhoea after drinking alcohol, especially beer.

There are several ways by which alcohol can cause diarrhoea. Below are some probable causes of your diarrhoea after drinking alcohol: 

• Alcohol is a diuretic, which increases urine production and can lead to the body losing too much water and electrolytes, causing dehydration. This diuretic effect can also cause the colon to absorb less water, resulting in loose stools⁸
• Alcohol may irritate the lining of the stomach and intestines, which make up the digestive tract, causing inflammation and increased bowel movements⁸
• Too much alcohol consumption can also inhibit the absorption of important nutrients in the gut, which can lead to malabsorption and diarrhoea⁸
• Some people may also be allergic to certain ingredients in alcoholic beverages, such as gluten or sulfites, which can cause diarrhoea³
• Additionally, drinking alcohol can disrupt the balance of good bacteria in the gut, leading to an overgrowth of bad bacteria and diarrhea⁴
• Alcohol can increase acid production in the stomach, further contributing to gut irritation and diarrhoea
• Some alcohol is sweetened with sorbitol, a type of poorly-absorbed sugar that can cause diarrhoea in some people⁴
• Alcohol can also cause the release of certain chemicals in the body that can lead to diarrhoea, such as histamine, which is found in beer and wine 
• When people with alcohol use disorders abruptly stop drinking heavily or continuously, whether on purpose or accidentally, they may experience alcohol withdrawal syndrome⁵

Management and treatment

The best way to prevent diarrhoea caused by alcohol is to limit or avoid alcohol consumption, specifically if you are at risk due to an underlying condition. However, there are several things that you can do to manage and treat alcohol-induced diarrhoea. 

• Drink lots of clear fluids to rehydrate the body and replace lost fluids and electrolytes. Avoid caffeine and sugary drinks, as they can further dehydrate you
• Avoid a high-fibre diet, dairy, spicy foods, or high-fat foods, as they may increase the frequency of your bowel movement 
• Eat foods that are easy to digest, such as rice, bananas, and toast, because they may also be beneficial as they do not put pressure on the gastrointestinal tract
• You may take probiotics to help restore your gut's health, as they increase the good bacteria in your stomach

If your diarrhoea is severe, you may take an over-the-counter medication, like loperamide (Imodium), to help control it. These medications work by slowing down bowel movement and can be effective in reducing diarrhoea. 

When should I call my doctor?

In most cases, diarrhoea caused by alcohol is not serious and can be managed with self-care measures. If your diarrhoea is accompanied by other symptoms such as severe abdominal pain, fever above 39℃, or blood in your stool, it is important to call your doctor immediately. These symptoms may suggest a more serious condition, such as an infection or an inflammatory bowel disease.

Additionally, if your diarrhoea lasts for more than a few days or you experience excessive dehydration or drastic weight loss, it is important to seek medical attention.

Furthermore, suppose you have an underlying medical condition that puts you at risk for complications from diarrhoea, such as HIV, kidney disease, or inflammatory bowel disease.^6,7 In that case, it is important to talk to your doctor about your alcohol consumption.

Summary

Several different factors, including alcohol consumption, can cause diarrhoea. Drinking alcohol can lead to diarrhoea for several reasons, ranging from increasing the speed of food and liquid through the large intestine, irritation of the gut and interference with the body's ability to absorb liquids and nutrients, and altering the balance of gut bacteria. It is best to limit or avoid alcohol consumption to prevent diarrhoea caused by alcohol; however, if you do experience diarrhoea after consuming alcohol, clear fluids, a bland diet, and over-the-counter medications can help to alleviate symptoms. Suppose your diarrhoea is severe, accompanied by other symptoms, or you have an underlying medical condition that puts you at risk for complications from diarrhoea, it is important to seek medical attention.