How Does Alcohol Affect Your Poop?

When you pour a glass of wine or you crack open a beer, you know the alcohol will affect your brain and maybe your mood.

But it also affects your digestive tract. How much, and even the type of alcohol, you drink can cause problems with your bowel movements.

Constipation

Even after moderate drinking, you may feel like you have trouble pooping. One of the main reasons is dehydration.

Alcohol keeps your body from releasing vasopressin, a hormone that helps your body hang onto fluid by preventing water from going out in your urine. Less vasopressin means you’ll need to pee more. But when your body gets rid of more fluid than normal, that can make you constipated.

The type of alcohol you drink may matter, too. Drinks with a high alcohol content -- more than 15% -- may slow down the movements of the muscles in your gut that push food through your digestive system. The amount of alcohol in typical drinks varies:

  • 12 ounces of regular beer: about 5%
  • 5 ounces of wine: about 12%
  • 1.5 ounces of liquor (such as gin, tequila, or vodka): about 40%

To keep things running smoothly, make sure you drink plenty of water or other fluids that will keep you hydrated.

Diarrhea

Diarrhea is common for chronic heavy drinkers, but it can also happen when you occasionally drink too much. There may be at least two reasons for this:

  • Fluid overload. The extra fluid in your gut isn’t related to how many ounces you drank. Instead, large amounts of alcohol prompt your intestines to release water. That flushes out whatever’s inside.
  • Faster contractions inside your colon. The muscles around your large intestine squeeze and push waste through. An alcohol binge puts this normal body process into overdrive.

Diarrhea means your body is losing a lot of liquid, so it’s important to replace it by drinking fluids like water or broth. Avoid caffeine or more alcohol until the problem goes away.

Drinking When You Have Bowel Problems

Research shows that people with inflammatory bowel disease (IBD), which includes Crohn’s and ulcerative colitis, drink about as much alcohol as anyone else in the U.S. But alcohol can trigger a flare for some people with these conditions. That could mean a period of:

  • Diarrhea
  • Belly pain and cramping
  • Blood in your stool

Continued

Alcohol makes the immune system weaker, boosts inflammation in the body, and can harm the protective barrier in your gut. These all contribute to the symptoms of IBD.

The effect of alcohol on people with irritable bowel syndrome (IBS) isn’t clear. But some people feel their symptoms get worse when they drink.

If you have a bowel disease like IBD or IBS, your doctor may suggest that you cut beer, wine, and liquor out of your diet to see if your symptoms improve.

Different Colors

You expect your poop to be some shade of brown. That’s normal, as are some shades of green. When it looks unusually green, red, or even blue, the alcohol you drank could be the cause.

Poop’s color comes from a combination of the food you eat plus a substance called bile, a yellow-green fluid that your body makes to digest fats. But certain things in your diet, including alcohol, can make your stool look different.

Say you have cocktails with green food coloring on St. Patrick’s Day. Your next bowel movement could be surprisingly green. If you have blue Jell-O shots or red punch, your stool could take on those colors. (It’s not just alcohol: Eating a lot of cranberries or leafy greens can also cause a color change.)

One thing to keep in mind if you see an odd color in the toilet: Rarely, it can signal a health condition. For instance, bright red poo could mean there’s blood in the lower part of your digestive tract, which could mean hemorrhoids or a problem somewhere else in your intestines. If you’re concerned about the color of your stool -- especially if you can’t link it to something you recently ate or drank -- give your doctor a call.

WebMD Medical Reference Reviewed by Minesh Khatri, MD on March 29, 2019

Sources

SOURCES:

Harvard Medical School: “This is your brain on alcohol,” “7 steps to cure your hangover.” 

National Institute on Alcohol Abuse and Alcoholism: “Alcohol Facts and Statistics,” “What is a Standard Drink?”

University of Michigan Medical School: “Constipation.” 

Reviews on Recent Clinical Trials: "The Effect of Alcohol on Gastrointestinal Motility.”

Addiction Biology: “Alcohol-related diarrhea.”

Mayo Clinic: “Inflammatory bowel disease,” “Stool color: When to worry.” 

Alcohol: “Pattern of Alcohol Consumption and its Effect on Gastrointestinal Symptoms in Inflammatory Bowel Disease.

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