Can someone become intoxicated without consuming alcohol? This puzzling scenario became reality for a 50-year-old woman in Canada, who visited emergency departments seven times over the past two years with severe symptoms of alcohol intoxication, despite not drinking alcohol on any of these occasions.

Doctors eventually diagnosed the woman with auto-brewery syndrome, a rare condition where the gut microorganism creates alcohol through fermentation, causing intoxication without drinking. This case was detailed in a report published in the Canadian Medical Association Journal (CMAJ)

What is gut fermentation?

During normal digestion, a very small amount of ethanol is naturally produced in the body. However, in patients with gut fermentation, also known as auto-brewery syndrome, there is an overgrowth of carbohydrate-fermenting fungi or bacteria in the gastrointestinal system, oral cavity, or urinary system. This overgrowth leads to significantly higher levels of ethanol production, reaching levels that can cause intoxication.

This condition is typically seen in individuals who consume a diet high in carbohydrates and refined foods, and can be exacerbated by the overuse of antibiotics and other drugs in both food and medicine.

People with a genetic disposition to conditions such as Crohn's disease, and short bowel syndrome have a higher risk of developing auto-brewery syndrome. Patients with chronic intestinal obstruction, gastroparesis (paralysis of the stomach), diabetes, or liver dysfunction such as non-alcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH) are also at high risk.

In the case described by CMAJ, the women had repeated urinary tract infections, which were treated with several courses of antibiotics.

"In our patient, we suspect her recurrent antibiotics for UTI and dexlansoprazole use led to gut dysbiosis with potential contribution of genetics, resulting in auto-brewery syndrome," the report stated.

What are the signs?

Patients with auto-brewery syndrome may experience symptoms of alcohol hangover, vomiting, belching, dizziness, loss of coordination, disorientation, fatigue, and irritable bowel symptoms. Chronic fatigue can also lead to anxiety, depression, and poor productivity.

In many cases, the patients face difficulties such as driving citations, strained social relationships, and injuries from falls. Due to the lack of standardized diagnostic techniques, auto-brewery syndrome is often diagnosed years after symptoms first appear. This delay can lead to prolonged suffering for patients, as the condition can be easily mistaken for other health issues.

"Auto-brewery syndrome may carry substantial social, legal, occupational, and medical consequences for patients, and awareness of this syndrome is essential for clinical diagnosis and management," wrote Dr. Rahel Zewude from the University of Toronto with other co-authors.


Treatment involves a combination of drugs, diet, and use of supplements. Patients with very high levels of ethanol in their bodies need immediate treatment to reduce the risk of acute alcohol poisoning. The typical treatment strategy includes using multi-strain probiotic supplements and drug therapy based on the culture and sensitivity results of the identified gut microbiome. Additionally, making specific dietary modifications, such as consuming a high-protein, low-carbohydrate diet, can help restore balance in the gut microbiome until symptoms subside.