FMT for Mental Illness is Experimental

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No clinical trial data has yet been published demonstrating the safety or efficacy of Fecal Microbiota Transplantation (FMT) for any mental illness, including bipolar disorder. While a few case studies exist—including my own (link to case study)—FMT remains entirely experimental in this context.

 

This presents an ethical dilemma for me. Until well-designed clinical trials are conducted and published, access to FMT for mental health conditions will remain limited, expensive, and inaccessible for most people. As a result, many individuals suffering from severe, treatment-resistant conditions such as bipolar I disorder or major depressive disorder (MDD) may feel they cannot wait for clinical approval. After hearing about my experience or those of others, some may decide to pursue DIY FMT in the hope of finding relief.

 

This deeply concerns me. DIY FMT carries significant risks, especially if the donor is not properly screened. A wide range of pathogens and conditions—including gastrointestinal infections, autoimmune diseases, and even neurological disorders like Alzheimer’s or Parkinson’s—could potentially be transmitted via fecal transplant. Even seemingly unrelated traits, such as baldness, may be affected; one friend of mine began losing hair after receiving FMT from his balding brother, with other reports of hair regrowth post-FMT in alopecia patients.

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Knowing that people may experiment with FMT despite the risks, I’ve created this resource to help reduce potential harm. It includes practical guidance on donor selection and screening and FMT preparation, as well as a list of FMT clinics in Australia and internationally.

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This is NOT an endorsement of DIY FMT.

Rather, it’s a harm-reduction effort born out of a deep sense of responsibility.

 

I’ve read distressing stories on DIY FMT forums—particularly among individuals with severe gastrointestinal conditions—where symptoms worsened after treatment. When it comes to mental illness, I personally know of a handful of cases where someone had a clearly adverse reaction to FMT. A friend in the USA with mixed-state bipolar disorder sourced FMT from a donor called "MG Infusions" and experienced acute suicidality within just a few days. Notably, she later used a donor from the Spanish stool bank Microbioma, and her suicidality resolved within two days—a striking contrast that underscores the importance of donor quality. A young French man with treatment resistant bipolar I disorder experimented with FMT using his twin brother as a donor. He experienced no adverse reactions after the first few enemas then developed manic symptoms that were attributed to the FMT. Other troubling temporary adverse reactions that have been reported have been a worsening of depressive and anxiety symptoms before an eventual improvement in both symptoms. In my own experience, I had no significant side effects, only some mild bloating for the first few hours while retaining the transplant. From others who have shared their experiences with me, common short-term symptoms included mild fever, fatigue lasting a few days, and bloating—all in line with side effects noted in clinical trials. 

 

It’s also important to acknowledge that deaths have occurred following FMT, including a well-known case involving a 73-year-old immunocompromised man who died after receiving stool from a donor carrying antibiotic-resistant bacteria. This tragic incident took place in a clinical setting and resulted from a failure to properly screen the donor. Since then, international screening protocols have been strengthened to include rigorous testing for antibiotic-resistant microbes to prevent such outcomes in the future.

 

Regarding the safety profile of FMT, a 2022 meta-analysis of 379 studies involving 5,099 patients found that serious adverse events occurred in less than 1% of cases within clinical settings. Mild side effects are more common but typically short-lived. These may include transient diarrhea, abdominal cramping or pain, low-grade fever, bloating, flatulence, and constipation, as detailed in the 2021 review “Fecal Microbiota Transplant: Is it Safe?” Both studies conclude that FMT is generally safe—provided the donor is thoroughly screened. However these studies were not conducted on people with mental illness specifically and without clinical trials it is impossible to know conclusively if FMT has a similar safety profile for people with mental illness.

The most important factor in minimising risk is rigorous donor screening. This is why I’ve created this resource: to help inform people about proper screening protocols and reduce preventable risks. If you’re considering FMT—especially a DIY approach—you are the only one who can assess whether the potential benefits outweigh the risks. That said, all medical interventions carry some level of risk, and even standard psychiatric medications can have serious adverse effects.

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Anecdotally I personally know of ~23 people who have experimented with FMT for a variety of mental illnesses with around ~75% success rate. 3 people with BP I, 13 with BP II, 1 OCD, 1 GAD and 3 MDD experienced significant symptom reduction. There are a number of people who have purchased FMT from Microbioma donor 2 and have not experienced any improvement in their symptoms whatsoever yet this same donor has resulted in significant symptom reduction in others. This illustrates the complexity of donor matching (something that is still a medical mystery). 

Though the number of people who try FMT for mental illness is growing, it is still a highly experimental therapy.

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For an overview of where the research is at I recommend this fantastic article published in August 2025 by Nature titled: "Why nurturing the gut microbiota could resolve depression and anxiety"