Auto-Brewery Syndrome

A rare, unstudied, unknown, underdiagnosed and underreported phenomenon 

Counterpoint Volume 7: Issue 1 - Article 5 (May 2023)

     Updated: November 2023; June 2024; November 2024

An article for participants in the myCAMprogram

Jan Semenoff, BA, EMA
​Forensic Criminalist

Article information:

1850 words (approximately 9-11 minutes)
​Auto-Brewery Syndrome (ABS) or gut fermentation syndrome is a rare condition in which ethanol is produced through endogenous (produced within the body) fermentation by fungi or bacteria in the gastrointestinal (GI) tract, in the mouth and oral pathway, or the urinary tract system. This condition can make your client impaired or intoxicated without consuming alcohol. It is often underdiagnosed.
You may also see ABS reported in the medical and forensic literature as EE production. EE stands for Endogenous Ethanol.
​Note that the increased BAC level is indicated by actual blood analysis. This is NOT a false-positive effect, or an interferent chemical creating an unreliable reading. They actually become impaired or intoxicated by the ethanol. their body is producing.
​A huge problem is that it can occur randomly and without warning, even among patients being treated for the condition through dietary control and medications. Unknowingly eat the wrong combination of carbohydrates, or be randomly exposed to the wrong yeast or bacteria, and the auto production of ethanol within the body will occur. The person can’t control it or stop it from occurring. The person will not even know it is occurring.
Patients with auto-brewery syndrome may present with some or many of the signs and symptoms of alcohol intoxication while denying the consumption of alcohol. They may not initially appear to have the signs and symptoms of intoxication but may report neurological symptoms, altered mental state, loss of coordination, and mood changes.
“Auto-brewery syndrome should be considered in any patient presenting with an elevated blood alcohol level who denies ingestion of alcohol, including those arrested for DWI”. (Painter, et al, 2022)

Causes

Several strains of fermenting yeasts [1] and rare bacteria [2] are identified as pathogens which cause ABS. These yeasts and bacteria are known to ferment carbohydrates into ethanol. In ABS, the condition is considered endogenous, or occurring naturally within the body.
[1] Fermenting yeasts such as Saccharomyces cerevisiae, Saccharomyces boulardii, and various strains of Candida, including Candida glabrata, Candida albicans, Candida kefyr, and Candida parapsilosis are identified as causes of this condition.

[2] The bacteria Klebsiella pneumonia, Enterococcus faecium, E. faecalis, and Citrobacter freundii are sometimes found in ABS patients.

Signs and Symptoms

Symptoms and side effects are consistent with having over-consumed alcohol:
  • red or flushed skin
  • dizziness
  • disorientation
  • headache pain
  • nausea and vomiting
  • dehydration
  • dry mouth
  • burping or belching
  • fatigue 
  • memory and concentration problems
  • mood changes

Diagnosis and Treatment

Diagnostic evaluation for ABS in carried out as follows:
  1. Suspected ABS (usually following an incident of impairment or intoxication without alcohol consumption).
  2. Detailed medical history and physical examination
  3. Positive breath and blood alcohol levels with no alcohol consumption
  4. Basic laboratory testing
  5. Endoscopy for intestinal visualizations and to obtain gut secretion samples
  6. Carbohydrate Challenge or Glucose Challenge testing for confirmation of ABS.
Treatment protocols can then be put in place which often include:
  1. Establishing a carbohydrate free diet
  2. Antifungal therapy, or
  3. The use of probiotic supplements.

Risk Factors

Auto-brewery syndrome, also known as gut fermentation syndrome, was first reported in the early 1940s.
​The disease has been identified in both male and female adults, children, and infants in many countries and is likely underdiagnosed. They often have a history of a high-sugar, high-carbohydrate diet.
​Auto-brewery syndrome has been reported in several patients with short bowel syndrome. Auto-brewery syndrome is more prevalent in patients with co-morbidities such as diabetes, obesity, and Crohn's disease but can occur in otherwise healthy individuals.
​Researchers compared patients with ABS to an asymptomatic group regarding lifestyle and health, diet, and medical history. The data show significant differences between the groups. The ABS group reported poorer overall health and more food sensitivities. 
​They often consume more water, with less tea and coffee, dairy products, and candy. The ABS members also report bad breath, diarrhea, and bowel changes. Most importantly, patients with auto-brewery syndrome report using antibiotics for a longer time. They also report more diagnosed GI disorders.

Metabolic Factors

​Measurements of endogenous ethanol have been made, and in one instance, a patient registered an ethanol concentration of greater than 0.400 grams/dL (g/dL). In these individuals, endogenous ethanol appears after the consumption of a high carbohydrate diet. Stress and skipping meals may also intensify these high ethanol levels.
​The normal fermentation of carbohydrates and sugars can produce ethanol. In diagnosing ABS through blood serum measurement, patients are made to fast in order to establish both baseline blood alcohol and blood glucose levels. They are then administered a dose of glucose in a Glucose Challenge test to see if there is an increase in blood alcohol as well as blood sugar. Blood glucose level can be measured with biosensors, as well as with urine test strips. Blood alcohol testing is also performed. 

History & Case Studies

​The syndrome has been reported and described in medical journals for more than 70 years, but remains misunderstood and perhaps underdiagnosed, with limited information for its diagnosis and treatment.
“Auto-brewery syndrome (ABS) is a rare, unstudied, unknown, and underreported phenomenon in modern medicine.”
​          Dinis-Oliveira RJ., “The Auto-Brewery Syndrome: A Perfect Metabolic "Storm" with Clinical and Forensic Implications”.
A Detailed History & Case Study

In 2019, researchers reported on a 25 year-old male, with no medical history of alcoholism, presented with a chief complaint of “drunk without drinking.” Two months previously, the patient noticed that he would feel very drunk after drinking his usual one or two 12-ounce beers in the evenings. This progressed to feeling drunk even when fully abstaining from alcohol. He continued to feel this way 1–2 times per week until his spouse decided to bring him to the emergency department during one of his “attacks.” (Akhavan, et al)
​His spouse described his symptoms as slurred speech, fatigue, stumbling, dizziness, and nausea. He would eventually “pass out” and wake up in the morning with no further symptoms. His symptoms were somewhat acute and often occur in the evenings, but without any identifiable trigger – specifically when he was not consuming alcohol.
​On further review, he had recently started a ketogenic diet for weight loss. He was not on any medications. His physical examination was normal with usual vital signs. 
​He did have an elevated lactic acid level and a blood alcohol concentration of 0.300g/dL (also elevated on a subsequent emergency department visit) in the complete absence of alcohol consumption. 
​On researching his condition, the patient’s spouse purchased a breathalyzer and found that without any alcohol consumption and while asymptomatic, he would register from 0.040 to 0.070g/dL. Each time the man had symptoms, he would perform a breath alcohol test with an elevated alcohol concentration, often in the 0.200g/dL range.

Other Reported Case Studies

  • In 2001, researchers reported on a 13 year-old female with short gut syndrome who had suffered repeated bouts of ABS with a BAC range of 0.250 - 0.350 g/dL. (Dahshan & Donovan, 2001)
It should be noted that in 2003, B. K. Logan and A. W. Jones wrote a letter to the editor of the journal that published the original study. They questioned the methods used in the initial reporting, and were concerned that the levels of ABS ethanol production were:
A ) higher than previously reported (Most endogenous ethanol production had been previously measured in "vanishingly small" levels), and
B) They were skeptical "that a 13 year-old girl could tolerate blood alcohol concentrations (that high) without suffering serious medical consequences such as acute alcohol poisoning."
  • A 3 year-old female with short bowel syndrome had ethanol levels of 22 mmol/L. This converts to a BAC of 0.101 g/dL. (Jansson-Nettelbladt, et al, 2006)
  • A 44 year-old male with gastrointestinal obstruction and intestinal bacteria was admitted to hospital. Subsequent blood alcohol tests showed a BAC of 24.9 mmol/L (millimol/L). This converts to a BAC of 0.115 grams/dL. His home-care attendant confirmed that there was no alcohol consumption. It was later determined to be ABS due to a simple sugar rich diet with  PPI (Proton Pump Inhibitor) therapy, often used by GERD patients. They used Widmark's formula to calculate the amount of alcohol that would be produced based on the sugar intake, and altered his diet. The ABS continued for 24 hours after admission to hospital, and discontinued upon dietary and medication changes. (Spinucci, et al, 2006)
​But, in the intervening years, more case studies were reported. In 2015, researchers (Cordell, et al) reported on three specific cases of ABS:
  • A 42 year-old female from Georgia who was a complete abstainer of alcohol who often appeared highly intoxicated. Her BAC was reported as “several times above the legal limit without consumption” when tested in the emergency department.
  • A 60 year-old male from Illinois who was a recovering alcoholic, sober for 23 years and an absolute abstainer of alcohol who was admitted for early dementia. It wasn't dementia. Confirmed ABS was elevating his BAC. Hospital testing reported his BAC level  as “0.170 g/dL without consumption.”
  • A 32 year-old male from Ohio who appeared highly intoxicated while suffering one of his bouts of a four-year long history of gastrointestinal distress. His BAC was reported between 0.240 - 0.340 g/dL on numerous days when he was confirmed not consuming any alcohol. (Cordell, et al, 2015)
And more case reports emerge:
  • ​In 2017, researchers reported on a 45 year-old male with Diabetes mellitus who had a BAC of 0.065 g/dL on admission to the hospital where he had no alcohol intake. He was assigned a 1:1 sitter who continuously monitored him establishing zero alcohol intake. It took more than 12 hours for him to completely eliminate the alcohol. Note that a person with a normal elimination rate will metabolize an 0.06 BAC in less than 4 hours. (Mishra & Seril, 2017). Blood testing confirmed ABS.
  • ​In 2019, researchers reported on a 46 year-old male with no medical history of alcoholism who was arrested and charged with OVI in Ohio with a reported BrAC of 0.200 g/dL. He denied consumption of any alcohol. When later tested by medical staff while hospitalized for a fall that caused a head injury, his BAC fluctuated daily from 0.040 - 0.150 g/dL. (Malek, et al)
  • ​In 2020, researchers admitted a 38 year-old male patient to hospital where he was kept under continuous observation with no possibility to consume alcohol of any kind. On admission, his BAC was measured at .0160 g/dL. At six hours it had doubled to 0.320 g/dL, then fluctuated between 0.210 - 0.280 g/dL up to 20 hours later before starting a slow decline. (Akbaba, 2020)
  • In 2023, physicians in Alabama reported the case of a 61 year-old male who presented at the emergency department with an altered mental state and a high blood alcohol concentration (0.287 g/dL). His family stated that he "drinks about 1 glass of bourbon every week". He denied drinking in the previous week. His blood alcohol concentration remained persistently high during his stay in hospital for treatment, where, of course, he did not consume any alcohol. (Shaw & Kewish, 2023)
  • A 50-year old female was referred to a gastroenterology clinic after 7 presentations at the ED with alcohol intoxication despite her confirmed zero alcohol consumption due to her religious beliefs. She would present to her family with indicia of impairment (slurred speech, smell of alcohol, and sudden unexpected falls). She presented at the ED with a BAC of 39 mmol/L ( 0.180 g/dL) on one occasion. The authors concluded:
Auto-brewery syndrome carries substantial social, legal, and medical consequences for patients and their loved ones. Our patient had several ED visits, was assessed by internists and psychiatrists, and was certified under the Mental Health Act before receiving a diagnosis of auto-brewery syndrome, reinforcing how awareness of this syndrome is essential for clinical diagnosis and management. (Zewude, et al, 2024.)
  • A 54-year old male, with a history of GERD, hypertension, and high cholesterol, presented to his family doctor after a recent hospitalization for altered mental status and an elevated BAC level. He strongly denied any alcohol use and mentioned similar events after consuming large meals. After witnessed alcohol cessation and an overnight fast, a glucose challenge test was positive for elevated blood alcohol levels. Researchers concluded that, "ABS is often under-diagnosed, with medical and legal implications. It should be suspected in patients showing signs of alcohol intoxication despite minimal alcohol consumption." (Khan, et al, 2024)
  • A 41-year old male was admitted to hospital for an ABS workup involving a glucose challenge test. He had a significant history of alcohol inebriation despite confirmed alcohol abstinence for the prior two years. Upon admission, his BAC was reported at 339 mg/dL. His subsequent home breathalyzer tests were positive despite confirmed alcohol abstinence. Researchers concluded, "A structured approach to diagnostic evaluation for this disorder is important for physicians, as the presence of ABS can have legal and occupational implications for patients." (Lee, et al, 2024)
If you're keeping track, that's 14 reported cases. I'm sure there are many others...

Final thoughts:

ABS is a "rare and underdiagnosed medical condition" (Shaw & Kewish, 2023). But keep in mind that if a disease has a low percentage of occurrence in a given population, it may be considered rare. However, if a disease is difficult to detect, regardless of clinical or diagnostic evaluation, it should be considered underdiagnosed.
So, was your client suffering from a rare condition, or one that is underdiagnosed?
More importantly, is it that rare? We have more than a dozen case-studies reported here alone.
Fermentation in the gut is a normal part of the digestive process and occurs through the breakdown of food by normal bacteria in the colon. However, in people with ABS, fermentation may occur further up the digestive tract, such as in the mouth, or farther down in the stomach, small intestine, and cecum.
However, some individuals might suffer from the consequences of being misdiagnosed as ethanol abusers, without consuming any ethanol, due to ABS. As we have seen, this rare syndrome affects people worldwide, and very little is known about the lifestyle, health, diet, and medical history of these patients.
For a more detailed look at ABS, see the comprehensive article:
Paramsothy, J, Gutlapalli, S, et al, "Understanding Auto-Brewery Syndrome in 2023: A Clinical and Comprehensive Review of a Rare Medical Disorder", Cureus. 2023 Apr 17;15(4):e37678.

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For further study:

  1. Akbaba M., A Medicolegal Approach to the Very Rare Auto-Brewery (Endogenous Alcohol Fermentation) Syndrome. Traffic Inj Prev. 2020;21(5):295-297.
  2. Al-Awadhi A, Wasfi I., “Autobrewing revisited: Endogenous concentrations of blood ethanol in residents of the United Arab Emirates”. Sci Justice, 2004;44(3):149–52.
  3. Bivin W, Heinen B., “Production of ethanol from infant food formulas by 49 common yeasts”, J Appl Bacteriol.1985;58(4):355–7.
  4. Cordell B, McCarthy J., “A case study of gut fermentation syndrome (auto-brewery) with Saccharomyces cerevisiae as the causative organism”, Int J Clin Med. 2013;4(7):1–4.
  5. Cordell B., “Auto-brewery as an emerging syndrome: Three representative case studies”. J. Clin. Med Case Rep. 2015;2:5.)
  6. Dahshan A, Donovan K., “Auto-brewery syndrome in a child with short gut syndrome: Case report and review of the literature”. J Pediatr Gastroenterol Nutr. 2001;33(2):214–5.
  7. Dinis-Oliveira RJ., “The Auto-Brewery Syndrome: A Perfect Metabolic "Storm" with Clinical and Forensic Implications”. J Clin Med. 2021 Oct 10;10(20):4637.
  8. Enache-Angoulvant A, Hennequin C., “Invasive Saccharomyces infection: A comprehensive review”, Clin Infect Dis.2005;41(11):1559–68.
  9. Guo X, Zhang W, & Huang R, et al., “The case study of one patient with gut fermentation syndrome: Case report and review of the literature”, Int J Clin Exp Med. 2018;11(4):4324–9.
  10. Kaji H, Asanuma Y, & Yahara O, et al., “Intragastrointestinal alcohol fermentation syndrome: Report of two cases and review of the literature”, J Forensic Sci Soc. 1984;24(5):461–71.
  11. Khan, T.K., Sorensen, L. et al, "A Case of Auto Brewery Syndrome (ABS) Complicating Cirrhosis and Leading to Liver Transplant", The American Journal of Gastroenterology, Volume 119, 2024.
  12. Kara I, Yildirim F, Özgen Ö, et al. “Saccharomyces cerevisiae fungemia after probiotic treatment in an intensive care unit patient”, J Mycol Med. 2017;28(1):218–21.
  13. Lee, C.S., Gancayco, J & Schwartz, M., "A Human Brewery: The Diagnostic Challenge of Auto-Brewery Syndrome", The American Journal of Gastroenterology, Volume 119, 2024.
  14. Logan BK, Jones AW., “Endogenous ethanol “auto-brewery syndrome” as a drunk-driving defence challenge, Med Sci Law.2001;40(3):206–15.
  15. Malik, F., Wickremesinghe, P, & Saleem, A., “Auto-brewery syndrome: A schematic for diagnosis and appropriate treatment”, Practical Gastroenterology, Series 212, July 2021.
  16. Malik F, Wickremesinghe P, & Saverimuttu J., “Case report and literature review of auto-brewery syndrome: probably an underdiagnosed medical condition”. BMJ Open Gastroenterol. 2019;6(1):e000325.
  17. Mishra A., Seril D.N., “Suspected Gut Fermentation Syndrome (Auto-Brewery Syndrome): 2519.” Off. J. Am. Coll. Gastroenterol. ACG. 2017;112:S1373. 
  18. Marteau PR, de Vrese M, Cellier CJ, & Schrezenmeir J., “Protection from gastrointestinal disease with the use of probiotics”, Am J Clin Nutr. 2001;73(Suppl 2):4.
  19. Painter K, Cordell BJ, & Sticco KL., “Auto-brewery Syndrome”, (Updated 2022 Dec 19), National Library of Medicine, National Center for Biotechnology Information.
  20. Paramsothy, J, Gutlapalli, S, et al, "Understanding Auto-Brewery Syndrome in 2023: A Clinical and Comprehensive Review of a Rare Medical Disorder", Cureus. 2023 Apr 17;15(4):e37678.
  21. Shah, Bhoomi MD & Kewish, Maria F. MD., "S2889 - Underdiagnosed Medical Condition: Auto-Brewery Syndrome". The American Journal of Gastroenterology 118(10S):p S1958, October 2023.
  22. Spinucci, G., Mariacristina, Gg, et al, "Endogenous ethanol production in a patient with chronic intestinal pseudo-obstruction and small intestinal bacterial overgrowth", European Journal of Gastroenterology and Hepatology, 2006, Vol 18 No 7.
  23. Zewude, R. T., Croitoru, K., et al, "Auto-Brewery Syndrome in a 50-Year-Old Woman", CMAJ 2024 June 3; 196:E724-7. Available at: www.cmaj.ca/content/196/21/E724