Evidence for motor and nonmotor benefits remains limited, researchers say
Written by Lila Levinson, PhD | June 10, 2026
- Fecal microbiota transplantation (FMT) shows promise for Parkinson’s-related constipation.
- FMT was generally safe and beneficial for gastrointestinal symptoms in people with Parkinson’s.
- Evidence for broader motor and nonmotor benefits is inconsistent, and more high-quality research is needed.
Fecal microbiota transplantation (FMT), a technique for replacing gut bacteria, may help with gastrointestinal symptoms of Parkinson’s disease, particularly constipation, according to a review study.
While the technique was found to be generally safe and beneficial for gastrointestinal symptoms in Parkinson’s disease, “at this stage, there is no convincing evidence that FMT produces a clinically relevant motor or non-motor symptomatic improvement on a group basis, at least in the short to medium term,” the researchers wrote.
Evidence on FMT remains limited
The researchers noted that available studies about FMT in Parkinson’s use a variety of different techniques, and many have methodological limitations. Future high-quality research could help clarify the potential benefits of FMT in this context.
The study, “Safety and efficacy of faecal microbiota transplantation in Parkinson’s disease,” was published in npj Parkinson’s Disease.
Parkinson’s is a neurological condition that leads to a variety of motor and nonmotor symptoms. Constipation and other gastrointestinal problems are among the possible nonmotor signs of the condition.
Parkinson’s and the digestive tract have a complex relationship. Not only can Parkinson’s cause gastrointestinal symptoms, but the bacteria and other microorganisms living in the intestines, collectively known as the gut microbiota, may influence certain disease processes. For example, the review noted that animal studies suggest that gut microbiota from people with Parkinson’s may promote inflammation and nerve degeneration.
These connections have led scientists to wonder whether altering the gut microbiota could be used as a treatment strategy for Parkinson’s. One way to do this is with FMT, which the researchers described as “an ultimate treatment for replacing the host microbiota with that of a healthy donor.”
There are several methods for performing FMT. Typically, they involve first collecting gut bacteria from donors’ stool. Patients receive the transplant as a capsule, an enema (a liquid placed into the rectum), or a procedure delivering the sample directly to the digestive system.
The team aimed to comprehensively examine existing research about FMT in Parkinson’s, which remains limited. “This review examines the current evidence on FMT in [Parkinson’s disease] concerning safety, efficacy, and microbiome changes, and analyses the data in the perspective of recommendations for future studies in this field,” they wrote.
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