Heidi Anderson came home to find her husband, Phil, on the front steps in a stupor. His son had just called him and then alerted Heidi to his disturbing demeanor, but Phil Anderson didn’t remember the call.
On another night, when Phil returned from walking their dog, he seemed unsteady and in a “trancelike state,” Heidi said. He told her he had fallen because his shoes were too big.
Phil’s zombielike spells became more frequent, coming on suddenly and usually in the evening. Heidi wondered if Phil, then in his late 50s, was developing dementia. She saw a therapist to learn how to cope.
He went to his doctor, who attributed the problem to dehydration. Later, after Phil drove the wrong way down a local parkway, Heidi insisted he seek additional medical care. A neurologist suspected seizures, but tests didn’t pinpoint a cause.
It was only after Phil stumbled and hit his head on a coffee table that a trip to the emergency room revealed a clue about what was triggering his disconcerting dazes.
That visit would eventually lead to a surprising diagnosis that has become more accepted in medicine in recent years.
“I was trying everything to get an answer,” Heidi said. “I never would have thought that something like this existed.”
A startling test result
Phil Anderson, now 69, spent 24 years in the U.S. Marines before working in homeland security and academic research. After running 13 marathons and completing an Ironman triathlon in his 20s and early 30s, he enjoyed mostly good health. There was an asthma diagnosis at 40, prostate inflammation at 50 and a stomach ulcer at 55. He took medications for high blood pressure and high cholesterol.
The bouts of altered mental states began in 2012, when he was living in Alexandria, Virginia, and training to become a Catholic deacon. Normally alert and gentle, Phil would become hypnotic and belligerent, arguing with Heidi or others before falling asleep on the couch. “It was a huge strain on our marriage,” she said.
After the couple moved to the Boston area in 2017, the episodes became more frequent and worrisome. They avoided dinners with friends, fearing Phil would slip into a spell. When Phil asked Heidi to sign a form allowing him to be ordained in 2019, Heidi finally convinced him to see more doctors and let her come along.
A neurologist ordered a brain MRI, which found that Phil had had some prior small strokes but didn’t explain his recent altered consciousness. A second brain scan, a brain electrical activity test, a sleep study and a six-hour psychological evaluation provided no answers.
A test of the electrical activity of Phil’s heart and an ultrasound of the main artery to his brain were normal. Images of his heart suggested a hole between the upper chambers, known as a patent foramen ovale. The common condition typically doesn’t cause symptoms, but it can increase the risk of strokes.
One night in August 2020, when Heidi came back from walking their dogs, Phil was on the porch in a haze. “He was just staring out into space,” she said. She ushered him inside, where he staggered and hit the coffee table.
At the ER, a blood test yielded a startling result: Phil’s ethanol level was 363 milligrams per deciliter, equivalent to a blood alcohol content of .363%, more than four times the legal limit for driving. But Phil was merely a casual drinker. And he was scheduled to have prostate-reduction surgery in a few days. In preparation, he swore he hadn’t had a drop to drink.
Elizabeth O’Brien, then in just in her second month as a full-fledged ER doctor, encouraged Phil to open up about any alcohol abuse and told him about treatment options. When he repeatedly denied drinking, O’Brien wondered if he might be telling the truth. She considered another explanation, she recalled in an interview.
O’Brien told Phil to look into a condition gaining more acceptance in medicine: auto-brewery syndrome. In the condition, intestinal microbes that break down carbohydrates produce unusually high levels of ethanol, leaving people in a drunken state.
Their guts essentially brew their own beer.
A search for a diagnosis
After Heidi contacted a nonprofit, Auto-Brewery Syndrome Advocacy and Research, she and Phil were connected with Bernd Schnabl, a gastroenterologist at the University of California at San Diego, who was conducting a study of people with signs of the condition. Phil signed up.
The trial, beginning in fall 2020, would set him on a course to understand what exactly was going on. But it was only the beginning.
He met with Prasanna Wickremesinghe, a gastroenterologist at Richmond University Medical Center in New York City, who with colleagues published a case study in 2019 about auto-brewery syndrome.
To determine whether this was the problem, “Dr. Wick,” as patients call him, conducted a glucose challenge test. Phil drank a sugary solution, which increased his blood alcohol level without consuming any alcohol. Then, Wickremesinghe collected samples from Phil’s digestive tract.
There, he uncovered a considerable growth of Saccharomyces cerevisiae, a fungus known as brewer’s yeast.
Wickremesinghe diagnosed Phil with auto-brewery syndrome.
The doctor prescribed nystatin, an antifungal medication, and Phil reduced his intake of carbohydrates and alcohol. For several months, the episodes went away.
But in August 2021, after more stumbling and confusion at home, Phil was back in the emergency room, with a blood alcohol content of .361%. The ER doctor, in consultation with Wickremesinghe, switched Phil to another antifungal, fluconazole. It seemed to help, but Phil still had periodic events.
“It’s like flipping a switch,” Phil said. “You’re perfectly normal one minute, and the next minute you’re toast.”
He and Heidi became distraught, wondering if the problem would ever go away. Phil took a leave from his deacon duties, fearing he would zone out while conducting a baptism or wedding. They bought a $1 million liability insurance policy in case his unpredictable behavior left someone injured. He tried acupuncture, coffee enemas and sessions in a sauna. He saw a naturopathic doctor, who prescribed a special probiotic pill for which the Andersons paid $1,500 a month. It didn’t stop the spells.
A new approach
Heidi read that fecal transplants, which have helped patients with intractable bacterial infections in their intestines, might benefit people with auto-brewery syndrome.
In the procedure, microbes from the processed feces of screened healthy donors are consumed in oral capsules, which can restore a healthy microbial ecosystem in the recipient’s gut.
Heidi contacted Elizabeth Hohmann, an infectious-disease specialist at Mass General Brigham medical center in Boston. Hohmann had administered hundreds of fecal transplants, mostly to patients with infections of bacteria known as Clostridioides difficile. In research studies, she also gave them to people with obesity, liver disease and conditions requiring bone marrow transplants.
Heidi pleaded with her to try a fecal transplant on Phil.
Hohmann was skeptical, she said in an interview. But she agreed to talk to Schnabl, the gastroenterologist in San Diego. She learned that when glucose was added to stool samples from Phil and other study participants in a lab bioreactor, ethanol levels in the samples shot up.
“That’s a pretty rigorous diagnosis that the microbiome is producing ethanol,” she said.
Bacteria, including Escherichia coli and Klebsiella pneumoniae, seemed to be driving the ethanol spikes in Phil and others, the researchers found. It wasn’t just yeast.
Phil had taken at least 18 courses of ciprofloxacin and other antibiotics over the years, mostly for his prostate inflammation, which may have caused an imbalance of bacteria in his gut.
“I believe that’s part of his problem,” Hohmann said.
Hohmann would get permission from the Food and Drug Administration to give Phil a fecal transplant. In November 2022, after taking three antibiotics for three days and drinking a colonoscopy prep solution to clear his intestines, Phil swallowed 15 capsules a day for five days to receive the transplant.
The treatment helped — at least for some time. But the episodes returned.
Hohmann gave him another fecal transplant in August 2023, using different antibiotics and followed by six monthly “boosters” of capsules, as she reported in a research paper with Schnabl and others this past January. That new approach seemed to work, too — until June 2025, when Heidi came home to find Phil lying by a bookcase with a cut above his eye.
He returned to the ER once more, with a blood alcohol content of .314%.
In July 2025, Hohmann gave him a third fecal transplant, repeating the approach of the second one, with monthly boosters that continue today.
Since then, Phil has been free of flare-ups.
He maintains a low-carb diet and has abstained from alcohol since March 2025. He’s back to regular deacon responsibilities, and playing golf and pickleball.
Heidi said his newfound stability is a relief after years of struggle.
“If we hadn’t had a strong marriage, I don’t know that we would have survived all of this,” she said.
For his part, Phil said he feels energetic again.
“I have my life back,” he said. “Every day is a beautiful gift.”
David Wahlberg has been a medical reporter for 30 years, including at the Atlanta Journal-Constitution and the Wisconsin State Journal in Madison.
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