It can be incredibly frustrating being constantly told that you have a drinking problem when you've never had a drop but for this 61-year-old Pennsylvania woman, each and every effort to become eligible for a life-saving liver transplant was thwarted by an insurmountable hurdle—she kept testing positive for alcohol. No matter how many times she asserted that she had not been drinking, her urine drug screens read otherwise. Accordingly, she was refused entry on the liver transplant waiting list numerous times, the doctors presuming she was struggling with alcohol addiction.But the reality was much stranger than anyone might have dreamed. In what seems to be a first in medical history, physicians found that her own bladder was secreting alcohol—a process so unusual that it had not been given an official name yet. Her case sheds new light on how the human body, under abnormal circumstances, can simulate effects of alcohol use without ingestion.The patient had severe liver cirrhosis, a scarring and liver function loss that requires a transplant to save her life. She also had diabetes that was uncontrolled, leading to high levels of glucose (sugar) in her urine.Initially, physicians at one hospital brushed off her assertion that she was sober, believing that she was denying alcohol addiction. When she subsequently reported for assistance at the University of Pittsburgh Medical Center (UPMC) Presbyterian Hospital, the same problem persisted. Her urine samples consistently registered the presence of ethanol, the beverage type of alcohol, further increasing the medical staff's suspicion. Yet there was a critical discrepancy: whereas her urine tested positive for ethanol, it was free of the usual metabolic byproducts—ethyl glucuronide and ethyl sulfate—seen days after drinking.This contradiction interested Dr. Kenichi Tamama, a senior researcher on the study and an associate professor of pathology and medical director of UPMC's Clinical Toxicology Laboratory. If the woman was consuming alcohol, the metabolites should have been found in her urine. Also, her blood alcohol tests were negative, and she never showed any symptoms of being intoxicated.Following more research, the doctors discovered a surprising cause: yeast in the woman's bladder was fermenting sugar into alcohol. The process, normally related to making beer or wine, was occurring within her body. Consequently, they suggested calling her condition "urinary auto-brewery syndrome" or "bladder fermentation syndrome."This condition is similar to, but different from, a rare disorder called auto-brewery syndrome (ABS), also referred to as gut fermentation syndrome. ABS happens when some microbes in the gut ferment carbohydrates into alcohol, leading to people with the condition becoming intoxicated without consuming alcohol. In the case of the Pennsylvania woman, however, her condition was confined to her bladder, so the alcohol did not reach her bloodstream. She therefore never seemed drunk, although her urine was ethanol-positive.To be sure about their suspicion, scientists performed an experiment. The researchers took a fresh urine specimen from the patient and incubated it at a temperature of the human body (98.6°F or 37°C). Ethanol in the sample zoomed within no time. The sample did not yield any alcohol, however, if it were incubated below normal temperature (39°F or 4°C) or after the addition of a chemical for stopping fermentation. This test conclusively established that the yeast in her bladder was the cause of the alcohol production.Additional lab tests determined the offender—Candida glabrata, a yeast that is normally present in the human microbiome. Candida glabrata is closely related to brewer's yeast, which is employed in alcoholic fermentation. Under conditions of excess sugar, as in the case of the woman with uncontrolled diabetes, Candida glabrata metabolized the glucose in her bladder to ethanol.Due to these observations, the woman was finally reevaluated for liver transplant, a move that could turn around her condition and save her life. Her case highlights the need to cast aside standard assumptions of diagnosis and to explore infrequent metabolic phenomena.Although sporadic reports of such cases have appeared, they were usually considered postmortem changes or laboratory artifacts due to the improper storage of urine samples. This case presents tangible evidence that bladder fermentation is possible in living patients and serves to increase awareness among medical professionals regarding distinguishing between true alcohol intake and endogenously produced alcohol.What Is Auto-Brewery Syndrome?Auto-brewery syndrome, or gut fermentation syndrome, is a rare condition where carbohydrates ferment to alcohol within the gastrointestinal tract. Patients can present with signs of intoxication, such as dizziness, slurred speech, and coordination impairment, without alcohol consumption. This results from an imbalance in gut microbiota, typically yeasts such as Candida.The syndrome is well-documented in medical literature for more than 50 years, yet it remains significantly underdiagnosed. A study published in 2021 estimated that fewer than 100 cases had been reported globally. Experts, however, estimate that numerous other people might be suffering from the condition unknowingly, as the symptoms might be confused with alcohol intake, metabolic conditions, or psychiatric issues. In severe instances, people with ABS have been charged with DUI, even though they consumed no alcohol.How Is Urinary Auto-Brewery Syndrome Different From Typical Auto-Brewery Syndrome?Urinary auto-brewery syndrome (bladder fermentation syndrome) and conventional auto-brewery syndrome (gut fermentation syndrome) are similar but differ significantly.In urinary auto-brewery syndrome, alcohol is synthesized in the bladder because of microbial fermentation of sugar. It may also happen in an open sample of urine outside the refrigerator. But as the alcohol is contained within the bladder and does not get into the bloodstream, individuals who have it do not have symptoms of being intoxicated.In contrast, classical auto-brewery syndrome happens within the gastrointestinal tract, where fermentative microbes metabolize carbohydrates into alcohol. This alcohol is absorbed into the bloodstream, resulting in a positive plasma ethanol reading and creating symptoms of intoxication similar to that following alcohol intake.