If you’ve ever had diarrhea after a night of drinking alcohol, it may not just be a coincidence.
Alcohol can irritate your digestive system, speeding up digestion and leading to loose, watery stools. We asked Karl Langberg, MD, a gastroenterologist with PACT Gastroenterology Center, a partner of Hartford HealthCare’s Digestive Health Institute, what you should know.
Here’s why alcohol can cause diarrhea, the risks to watch for and when it’s time to see a doctor.
Alcohol affects your whole digestive system.
If you’ve ever experienced an upset stomach or diarrhea after drinking, you’re not imagining it — alcohol and your digestion don’t mix.
“Alcohol has a huge impact on digestion, affecting nearly every part of the digestive system,” says Dr. Langberg.
It can lead to a range of issues, including:
- Gastroesophageal reflux.
- Stomach inflammation.
- Weight gain.
- Increased risk of liver disease.
- A contributing factor to hemorrhoids.
- An increased risk for most gastrointestinal cancers.
“Alcohol also disrupts the ability to absorb nutrients,” he adds. “It affects the lining of the small bowel, causing water and salt to leak into the stool. That’s why many people experience watery, urgent diarrhea after drinking.”
People with conditions like irritable bowel syndrome (IBS), inflammatory bowel disease or celiac disease may be more sensitive to alcohol’s diarrhea-causing effects, though this isn’t well-studied.
> Related: Is Alcohol Giving Me Acid Reflux?
Drink choice matters, but quantity matters more.
While research on this question is limited, some drinks may trigger diarrhea more than others.
According to Dr. Langberg, you may want to think twice about:
- Sweet drinks.
- Alcohol mixed with sugar, corn syrup or artificial sweeteners.
- Dairy-based beverages like Irish cream, certain cocktails or some craft beers.
“It’s less about the type of alcohol and more about how much you drink,” explains Dr. Langberg. “Most studies on alcohol and diarrhea focus on individuals with alcohol use disorder. The more you consume, the higher the likelihood of diarrhea, but it can vary significantly from person to person.”
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The health risks of alcohol don’t end with digestion.
Alcohol’s impact on health has often been misunderstood, with many believing it’s harmless—or even beneficial.
But research paints a different picture, with growing evidence of alcohol’s carcinogenic effects.
“Alcohol is a significant contributor to many digestive health problems,” says Dr. Langberg. “It’s a major cause of liver disease and cirrhosis. It can also lead to acute and chronic pancreatitis—painful and potentially life-threatening inflammation of the pancreas. Plus, it’s a leading risk factor for esophageal, stomach and colorectal cancers.”
When to see your doctor.
Some symptoms are too concerning to ignore.
Dr. Langberg shares when it’s time to seek medical attention:
- Diarrhea more than five times a day for over two to three days.
- Blood in your stool or black, tarry stools.
- Yellowing of your skin or the whites of your eyes.
- Diarrhea that wakes you up at night.
“It’s also important to recognize if you may have an unhealthy relationship with alcohol,” adds Dr. Langberg. “If alcohol regularly contributes to your diarrhea, you’re drinking in the morning, feel annoyed when others comment on your drinking, often exceed one to two drinks per day or struggle to cut back, please talk to your doctor. They are here to help.”
