This Man’s Body Secretly Produced Alcohol, And He Kept Getting Drunk Without Drinking

When Florida resident Mark Mongiardo quit drinking alcohol in 2018, he thought his health problems would finally improve. Instead, he kept experiencing episodes that looked exactly like drunkenness. He would become dizzy, confused, slur his speech and sometimes struggle to walk properly. At one point, he reportedly failed a breathalyser test despite insisting he had not consumed alcohol at all.

According to reports in the US media, Mongiardo was later diagnosed with a rare condition called auto-brewery syndrome, a disorder in which the body itself starts producing alcohol internally. Doctors discovered that microbes inside his digestive system were fermenting carbohydrates into ethanol, effectively turning his gut into a miniature brewery.

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condition sounds almost unbelievable, which is partly why many patients spend years being doubted before receiving a diagnosis. In some cases, people have reportedly faced drunk-driving charges, lost jobs or damaged relationships because others assumed they were secretly drinking.

Auto-brewery syndrome is extremely rare, but researchers now believe it may also be underdiagnosed because many doctors are unfamiliar with it. The disorder happens when certain fungi or bacteria in the digestive system begin converting sugars and carbohydrates into alcohol faster than the body can process it.

Normally, the human gut produces only tiny traces of ethanol during digestion. But in auto-brewery syndrome, the fermentation becomes excessive. After eating carbohydrate-heavy meals like bread, pasta, rice or sweets, some patients can develop genuine symptoms of intoxication within hours.

Researchers have identified several microbes that may trigger the condition, including strains of yeast and bacteria such as Klebsiella pneumoniae. Long courses of antibiotics are considered one possible cause because they can disrupt the balance of healthy bacteria in the gut and allow alcohol-producing organisms to multiply.

One of the reasons the condition attracts so much attention online is because it sounds like science fiction. Yet medical journals have documented cases from around the world for years. In Belgium, a court recently cleared a man accused of drunk driving after doctors confirmed his body was producing alcohol naturally through auto-brewery syndrome.

Doctors say symptoms can range from mild brain fog and fatigue to severe intoxication. Some patients reportedly reach blood alcohol levels high enough to exceed legal driving limits despite never consuming alcohol. The condition may also cause nausea, bloating, headaches and chronic exhaustion.

Treatment usually involves strict low-carbohydrate diets alongside antifungal or antibiotic medications aimed at controlling the microbes responsible for fermentation. In particularly severe cases, doctors have even experimented with faecal microbiota transplants, where healthy gut bacteria from a donor are introduced into the patient’s digestive system.