Auto-brewery Syndrome (Gut Fermentation)

Article Author:
Kelly Painter
Article Author (Archived):
Barbara Cordell
Article Editor:
Kristin Sticco
9/21/2019 11:20:42 PM
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Auto-brewery Syndrome (Gut Fermentation)


Auto-brewery syndrome or gut fermentation syndrome is a condition in which ethanol is produced through endogenous fermentation in the gastrointestinal (GI) system. Spontaneous ethanol production occurs via a different metabolic pathway. Auto-brewery syndrome occurs in patients with alcohol intoxication after they ingest carbohydrate-rich meals.

Saccharomyces cerevisiae, a type of yeast, is identified as the pathogen. Endogenous fermentation or auto-brewery syndrome has been used as a defense against drunk driving charges although there is no literature quantifying the success rate of raising this defense. However, it is unlikely auto-brewery syndrome would cause significant levels of blood alcohol that would be high enough to induce intoxication that would produce illegal levels of blood alcohol.

A variation of the disease occurs in individuals with liver dysfunction that prevents them from excreting alcohol in a normal fashion. Patients develop signs and symptoms of auto-brewery syndrome when the yeast in the gut produces a quantity of alcohol that is too meager to induce intoxication in a normal individual but may induce signs and symptoms in individuals afflicted with auto-brewery syndrome.[1]


Saccharomyces cerevisiae is a yeast identified as the pathogen that causes auto-brewery syndrome.

  • It has been reported as a complication of Crohn's disease in adults.[2]
  • Auto-brewery syndrome has occurred in a child with short bowel syndrome who signs and symptoms of alcohol intoxication. Cultures from gastric fluid and feces demonstrated the presence of Candida kefyr. An association was found between a carbohydrate-rich fruit drink and symptoms and signs of the auto-brewery syndrome.[3][4]
  • Auto-produced ethanol might explain a rare etiology of sudden infant death.

Four common yeasts (Candida albicans, Candida tropicalis, Saccharomyces cerevisiae, and Torulopsis glabrata) were combined with infant formulas. Ethanol production was measured after 24 and 48 hours. The quantities of ethanol produced suggest an explanation for patients exhibiting auto-brewery syndrome.[5]


This is a rare condition. The disease has been identified in both adults and children.


Saccharomyces cerevisiae has been identified as the cause of this condition. Although yeasts such as Candida albicans may produce ethanol in-vitro, whether this happens in healthy subjects has not been established. Determinations of endogenous ethanol have been made, and in rare instances, a high ethanol concentration (greater than 80 mg/dl) has been identified. In these rare individuals, endogenous ethanol appeared to have been produced after consumption of a high carbohydrate diet.

A genetic polymorphism that results in reduced activity of enzymes involved in the hepatic metabolism of ethanol and a first-pass metabolism might explain the ethnic differences in rates of endogenous ethanol production and clearance. Reports of abnormally high concentrations of ethanol in body fluids from ostensibly healthy subjects suffer from deficiencies in study design or use non-specific unreliable research methods.

With reliable gas chromatographic methods of analysis, the concentrations of endogenous ethanol in the peripheral venous blood of healthy patients, as well as those suffering from metabolic disorders such as diabetes, cirrhosis, or hepatitis ranged from 0 to 0.08 mg/dl.[1] These concentrations are too low to be significant. The notion that intoxication of a motorist was a direct result of endogenously produced ethanol has as yet not been scientifically demonstrated.[6]

History and Physical

Auto-brewery syndrome has significant effects on life. The patient may experience side effects of belching, chronic fatigue syndrome, dizziness, dry mouth, disorientation, hangovers, and irritable bowel syndrome. The chronic fatigue syndrome can result in health problems such as anxiety, depression, and poor productivity. The random state of intoxication can result in difficulties, and the obscurity of the condition may make it difficult to diagnose and find a successful treatment.

The patient's dietary intake should be carefully evaluated.


Auto-brewery syndrome is possible in any patient with chronic obstruction or hypomotility that presents with elevated serum ethanol levels and high carbohydrate intake and no history of alcohol consumption. Because of the production of significant alcohol levels, people can test over the legal driving limit without having consumed any alcohol.

  • Evaluation should include a blood alcohol screen and drug screen.
  • CT enterography may demonstrate massive dilation of the small bowel with anastomotic stricture.

The possibility of endogenous ethanol fermentation should be considered in patients with SBS and included in the differential diagnosis list for D-lactic acidosis.

Treatment / Management

The treatment of auto-brewery syndrome is a modification in the diet requiring high protein and low carbohydrates.

Sugar is fermented into alcohol, a diet that lowers sugars will decrease the alcohol fermented from the gastrointestinal tract. Anything that causes an imbalance between harmful and beneficial bacteria can potentially increase fermentation in the gut. This may include antibiotics and the overindulgence in sugars and carbohydrates.[7]

Lower the risk of gut fermentation syndrome by avoiding carbohydrates and taking probiotics that increase normal bacteria in the gastrointestinal tract.

Use of antibiotics, carbohydrate control, and antifungal therapy have all been reported as successful treatments. Clinical consideration and diagnosis of auto-brewery syndrome should be made with caution, considering the lack of validated scientific evidence and a mechanism linking endogenous ethanol production to peripheral blood ethanol.

Differential Diagnosis

Auto-brewery syndrome should be considered in the differential diagnosis of patients that are not consuming alcohol and yet exhibit the signs and symptoms of alcohol consumption; particularly if they are also consuming a high carbohydrate diet.


With antibiotics and diet modification, most symptoms resolve.


Auto-brewery syndrome is known to have a profound effect on patients and families. In many cases, it is mistaken for alcohol consumption. This can be problematic when a victim of the disease denies alcohol intake but has the signs, symptoms, and possible breath of someone that has been drinking alcohol.

Postoperative and Rehabilitation Care

Diet modification usually abates symptoms with antibiotic therapy and probiotics.


Consult gastroenterology and a registered dietician.

Deterrence and Patient Education

A patient should avoid a high-carbohydrate diet and eat a diet higher in proteins.

Enhancing Healthcare Team Outcomes

Auto-brewery syndrome (gut fermentation syndrome), although very rare, is a medical condition that may occur in patients ingesting high carbohydrate-rich meals. The healthcare team should be aware of the slight possibility of this condition. If there is no alcohol intake, and other more common toxicologic causes of signs and symptoms of intoxications are ruled out, this disease should be considered as a possible cause of the patient's signs and symptoms and empathetic care should be provided. In addition to blood alcohol, it would be appropriate to consider a drug screen. [Level V]


[1] Auto-brewery syndrome: Ethanol pseudo-toxicity in diabetic and hepatic patients., Hafez EM,Hamad MA,Fouad M,Abdel-Lateff A,, Human & experimental toxicology, 2017 May     [PubMed PMID: 27492480]
[2] Auto-brewery Syndrome in the Setting of Long-standing Crohn's Disease: A Case Report and Review of the Literature., Welch BT,Coelho Prabhu N,Walkoff L,Trenkner SW,, Journal of Crohn's & colitis, 2016 Dec     [PubMed PMID: 27161390]
[3] Endogenous ethanol fermentation in a child with short bowel syndrome., Jansson-Nettelbladt E,Meurling S,Petrini B,Sjölin J,, Acta paediatrica (Oslo, Norway : 1992), 2006 Apr     [PubMed PMID: 16720504]
[4] Auto-brewery syndrome in a child with short gut syndrome: case report and review of the literature., Dahshan A,Donovan K,, Journal of pediatric gastroenterology and nutrition, 2001 Aug     [PubMed PMID: 11568528]
[5] Production of ethanol from infant food formulas by common yeasts., Bivin WS,Heinen BN,, The Journal of applied bacteriology, 1985 Apr     [PubMed PMID: 3997687]
[6] Endogenous ethanol 'auto-brewery syndrome' as a drunk-driving defence challenge., Logan BK,Jones AW,, Medicine, science, and the law, 2000 Jul     [PubMed PMID: 10976182]
[7] Chocolate and the auto-brewery syndrome., van Lieshout A,, Lancet (London, England), 1990 Nov 3     [PubMed PMID: 1978005]