Researchers at Virginia Commonwealth University have found fecal transplants may be helpful in reducing drinking behaviors in those suffering severe alcohol use disorder (AUD). The work points to a compelling relationship between the gut microbiome and addiction disorders, with large-scale Phase 2 human trials currently underway.
Editor's note: Readers often ask us for follow-ups on memorable stories. What has happened to this story over the years? This article was originally published in 2020 but it has been re-edited and updated with new information current as of May 1, 2025. Enjoy!
The idea fecal microbial transplants (FMT) can improve human health is not new. Modern medicine has been experimenting with the treatment for well over half a century, and Chinese medical practitioners have used the technique for millennia. Over the last decade, however, interest in fecal transplantation has surged, alongside frequent breakthroughs in gut microbiome research.
This current research focuses on the relationship between addiction and the gut microbiome. More specifically, the investigators set out to explore whether a FMT can positively influence drinking behavior in subjects suffering from alcoholism.
“People with alcohol use disorder are often discriminated against and given up on,” said Jasmohan Bajaj in 2020, lead researcher on the project. “But it’s a disease like any other. There’s a genetic predisposition, and addictions may be promoted by those gut microbes.”
Prior animal studies have indicated FMT can improve negative alcohol-induced behaviors, but this current research offers the first robust, placebo-controlled data in humans. The preliminary Phase 1 trial recruited 20 subjects with clinically diagnosed alcohol-use disorder. The cohort was all male, in their mid-60s, and suffering alcohol-related cirrhosis of the liver.
The cohort randomly received either a placebo or active FMT gathered from a single donor high in Lachnospiraceae and Ruminococcaceae, two types of gut bacteria seen in low levels in AUD patients. After one FMT, administered via enema, a variety of physiological and behavioral factors were measured at two follow-up points – 15 days and six months.
“Nine of 10 patients that received the transplant actually had reduction in their cravings and a reduction in the urine measurement of alcohol-related metabolites,” Bajaj explained, referring to the first 15-day follow-up. “They reduced their drinking, objectively.”
This compared to only three of the 10 placebo subjects displaying similar levels of improvement.
Needless to say, this was just a small preliminary study, so the researchers caution against forming any broader conclusions regarding the efficacy of FMT for alcoholism. The Phase 1 trial essentially served as a proof-of-concept, establishing the treatment as safe.
“We conclude in this Phase 1 trial that FMT in men with cirrhosis is safe, associated with reduction in short-term craving and consumption with beneficial microbial change,” the researchers wrote in the conclusion to the study reporting preliminary data in 2020. “The FMT-assigned group also demonstrated lower AUD-related events over the follow-up, which need to be confirmed and extended in larger number of patients with AUD.”
Since that initial trial, work has progressed slowly but promisingly. A larger Phase 2 trial is currently underway, looking to recruit around 80 participants with sustained alcohol use disorder. As of early 2025 Bajaj tells New Atlas the trial is about 70% enrolled. With a follow-up period of around six months it is hoped early data emerges sometime in 2026.
The research team is also working to optimize the composition of the FMT given to patients. Work is underway into finding a fecal donor sample that works best for alcohol addiction. A study from Bajaj and colleagues published in 2022 found stool samples collected from Phase 1 trial participants at the end of the experiment were successful in reducing alcohol-seeking behaviors when transplanted into mice.
The Phase 1 study was published in the journal Hepatology.
Original Source: Virginia Commonwealth University
An earlier version of this article was published in 2020.
