Auto-brewery syndrome, also known as gut fermentation syndrome, is a rare medical condition in which intoxicating quantities of ethanol are produced through endogenous fermentation within the digestive system. One gastrointestinal organism, Saccharomyces cerevisiae, a type of yeast, has been identified as a pathogen for this condition.
It can occur in patients of short bowel syndrome after surgical resection because of fermentation of malabsorbed carbohydrates.
One case went undetected for 20 years.
A variant occurs in persons with liver abnormalities that prevent them from excreting or breaking down alcohol normally. Patients with this condition can develop symptoms of auto-brewery syndrome even when the gut yeast produces a quantity of alcohol that is too small to intoxicate a healthy individual.
This disease can have profound effects on everyday life. As well as the recurring side effects of excessive belching, dizziness, dry mouth, hangovers, disorientation, irritable bowel syndrome, and chronic fatigue syndrome, it can lead to other health problems such as depression, anxiety and poor productivity in employment. The random state of intoxication can lead to personal difficulties, and the relative obscurity of the condition can also make it hard to seek treatment. 
A breathalyser, as administered by a professional, would determine if alcohol was present in the system. This may have to be repeated at multiple times of the day to account for naturally occurring fluctuations and to build up a bigger picture of how the condition manifests itself.
The treatment for auto-brewery syndrome is a change in diet requiring low carbohydrates and high protein. Sugar is fermented into alcohol, and a diet that effectively lowers sugars also lowers the alcohol that can be fermented from it. Anything that causes an imbalance between the beneficial and harmful bacteria in the gut can help increase the chance that fermentation in the gut will develop. This can include not only antibiotics, but also overindulgence in sugars and carbohydrates. Watching what you eat could lower the risk of gut fermentation syndrome, and taking probiotics could further protect you by increasing the number of good bacteria in your system.[better source needed]
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- “Auto Brewery Syndrome – What It Is, and How to Deal With It.” Gundry MD, 13 Apr. 2017, gundrymd.com/auto-brewery-syndrome/.
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