What Happens to Your Gut Microbiome When You Drink Alcohol, According to a Gastroenterologist

Alcohol's effect on the body can be considered a controversial matter. While it's clear that drinking a cocktail every day can negatively affect your heart health and sleep cycle, what if you're just enjoying an occasional night out? It may be time to rethink any alcoholic drink, according to this gut doctor.

"People always want to know, 'Dr. B, what does alcohol do to my gut microbiome?'" says gastroenterologist and cookbook author Will Bulsiewicz, M.D., in an Instagram video. "Well, it's very clear that heavy alcohol consumption is bad for our gut. The question is, what if you're just having one night with, you know, at least a moderate amount of alcohol?"

Bulsiewicz breaks down the science on how a night of drinking can impact the gut. Read on to learn more—as well as appropriate ways to include alcohol in a healthy eating pattern.

"They did a study on this and what they found, which was fascinating, is that within 30 minutes of drinking alcohol, you will already see it make an impact on your gut microbiome," Bulsiewicz explained, referencing this 2014 study published in PLoS One. "And the reason why we know this is because bacterial endotoxin levels—this is a toxin that can cause inflammation—actually start to rise within 30 minutes of people consuming the alcohol."

Alcohol causing inflammation in the body isn't shocking news—trust me, I know it firsthand—but what is surprising is its direct impact on the gut. A 2024 review published in Alcohol Clinical & Experimental Research further supports these findings. The study shows that drinking alcohol regularly can change the bacteria in your gut, leading to digestive problems like irregular bowel movements and diarrhea.

"Bottom line, I just don't buy that alcohol is actually better for you," Bulsiewicz said at the end of his video. "I think we're better off without it, but it is fun."

Don't be discouraged: For most people, an occasional drink can be included in a healthy eating pattern. Bulsiewicz even admits in his Instagram video caption that he'll "still have a beer or glass of wine if out with friends," but being mindful is key. Sipping alcohol in moderation is the best way to enjoy it in your healthy diet.