The little-known condition that can make you drunk without drinking has been explained by an expert

Imagine experiencing the symptoms of being drunk after eating a plate of pasta, despite not having touched a drop of alcohol.

For people with auto-brewery syndrome (ABS), this unusual scenario can become a frightening reality.

The rare condition, also known as gut fermentation syndrome, occurs when microorganisms in the digestive system convert carbohydrates into ethanol, which enters the bloodstream and can cause intoxication.

Dr. Savita Srivastava, a Yale-trained gastroenterologist and microbiome specialist at DoctorSavita.com, describes it as a condition in which the digestive system effectively becomes an internal brewery.

"Auto-brewery syndrome, also known as gut fermentation syndrome, is a rare and bizarre medical condition where your gastrointestinal tract literally operates an internal microbrewery," she explained.

But while the description might sound unusual, the consequences can be serious, ranging from impaired coordination and confusion to potential liver damage and legal complications.

ABS as a very rare disorder characterised by alcohol being produced inside the body - it can cause symptoms resembling alcohol intoxication. (Getty Stock Image)

What causes auto-brewery syndrome?

Dr. Edmundo A. Rodriguez-Frias, a dual-board-certified gastroenterologist and geriatrician, explained that ABS develops when alcohol-producing gut microbes or their activity become unusually prominent.

"Auto-brewery syndrome is a rare disorder in which gut microbes ferment dietary carbohydrates into ethanol, which enters the bloodstream and can cause intoxication without alcohol consumption," he said.

Antibiotic use and changes to gastrointestinal anatomy may contribute to the condition.

Dr. Srivastava also identifies intestinal disorders and diabetes as potential contributing factors.

"But when that ecosystem suffers severe dysbiosis, often triggered by high doses of antibiotics, chronic intestinal conditions like Crohn’s or short gut syndrome, or underlying diabetes, fermenting microbes take over," she said.

"When a person with ABS eats everyday carbohydrates: a plate of pasta, a slice of bread, or a sugary drink, these overpopulated microbes consume those carbs and turn them into pure endogenous ethanol (alcohol) via fermentation," she explained.

Research is providing further clues about which microorganisms are involved.

A 2026 Nature Microbiology study of 22 confirmed patients found an enrichment of bacteria including Escherichia coli and Klebsiella pneumoniae.

Dr. Rodriguez-Frias said the findings suggest 'bacteria may be important rather than yeast alone.'

r. Edmundo A. Rodriguez-Frias says patients can experience confusion, impaired coordination and intoxication without consuming alcohol (QWOTED).

What are the symptoms and treatments for auto-brewery syndrome?

The condition can cause episodes of intoxication, confusion and impaired coordination, even without alcohol consumption.

Dr. Srivastava said: "In the short term, patients experience severe unexplained intoxication, slurred speech, loss of motor coordination, brain fog, nausea, and debilitating hangovers after eating high-carb meals."

Dr. Rodriguez-Frias warned that the complications can extend beyond individual episodes.

"Repeated internal ethanol exposure may also injure the liver," he said, adding that severe liver disease has been reported, although long-term risks remain uncertain.

Patients may also face accusations of drinking, employment difficulties and legal consequences if alcohol is detected during a roadside test.

"The diagnosis is not accepted uniformly as a legal defense," Dr. Rodriguez-Frias explained, making thorough medical evaluation and objective testing particularly important.

Diagnosis typically involves excluding other causes and measuring alcohol levels under controlled medical supervision. A glucose challenge test can help establish whether ethanol levels rise after carbohydrate consumption.

Treatment depends on the individual and may involve targeted antimicrobial medication and dietary carbohydrate modification.

Patients may also face accusations of drinking and employment difficulties. (Getty Stock Image)

Dr. Rodriguez-Frias said options "may include targeted antimicrobial therapy, dietary carbohydrate modification, and sometimes probiotics as an adjunct, although evidence is limited."

Faecal microbiota transplantation (commonly known as stool transplant) has also produced remission in a reported case, but it remains investigational rather than an established treatment.

Dr. Rodriguez-Frias stressed that recovery does not necessarily mean the condition has been permanently resolved.

"The long-term outlook can be favorable when the microbial imbalance and contributing factors are controlled, but relapse is possible," he said.

He added that patients generally need follow-up to monitor recurring symptoms and liver health.

For Dr. Srivastava, raising awareness remains essential. "The real hurdle isn't treatment-it’s awareness," she said.