Faecal transplant
Also called: FMT, faecal microbiota transplant, stool transplant.
Last reviewed 2026-09-16. How this works.
When to call your team
If you have had a faecal transplant, contact your care team the same day if you notice:
- a fever, or feeling hot and shivery
- severe or bloody diarrhoea
- stomach pain that is getting worse
- feeling suddenly very unwell, faint or confused
Infections have been transmitted by this procedure, including one that caused a death, in people whose immune systems were suppressed. These are reasons to seek advice urgently. They are not a diagnosis, and this page cannot tell you what is causing them.12
These are reasons to make contact, not a diagnosis. If this is something you are considering or have already had done, the people treating you can only weigh it if they know about it.
This block is about what to watch for, and it is not all this page holds: what has been recorded about harm is below. Nothing in this block is an all-clear for a question it does not mention.
Immunotherapy-refractory melanoma Grade C
Human evidence exists and does not settle it.
Harm has been recorded in people for this claim. The grade measures how strong the evidence for benefit is; it says nothing about the harm, and the two are read from different parts of this page.
In small early studies some melanoma patients responded again after this, and bigger trials are running.
Early-phase responses, and it is being tested properly.
The harm
Two immunocompromised adults who received investigational faecal transplant developed invasive infections with a drug-resistant organism. One of them died. Both preparations came from the same donor, and neither had been tested for that organism before use.1
The population in that report is exactly the readership of this register: people whose immune systems are suppressed. A regulator issued a safety alert in 2020 about further infections, six cases with four hospitalised, and another in 2022 about a different transmissible infection.12
This is the reason the entry says what it says about where to receive it. A transplant inside a trial comes with donor screening that has been revised in response to these events. One arranged privately does not.1
The claim
The claim is that transferring gut bacteria from a donor who responded to immunotherapy can make the treatment work in someone it has stopped working for.
What it does
If the gut microbiome shapes the response to checkpoint immunotherapy, then replacing it wholesale is the most direct possible test of that idea. This entry exists because the idea is being tested rather than argued about.
The evidence
Early-phase studies have reported responses in people whose melanoma had stopped responding to immunotherapy. These are small, early, and not controlled, and the book grades them as such.1
What separates this from most of the register is that it is in the hands of people running registered trials rather than being sold. The honest position is promising and unproven.
The studies this rests on
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Early-phase faecal transplant in immunotherapy-refractory melanoma1
A trial with no comparison group, open label, phase 1, measured a clinical outcome.
responses reported in some patients whose melanoma had stopped responding to immunotherapy.
What is absent
No controlled trial of faecal transplant for melanoma has reported. The responses described come from small early-phase studies without a comparison group.
Scope: any tumour type, any endpoint.
Established by trial scope, checked 2026-09-16. Result: the human studies recorded here are early-phase and uncontrolled.1
What to ask
Is there a faecal transplant trial I could be considered for, rather than arranging anything privately?
The dish-to-person gap
This transfers a community of organisms rather than a compound, so no pharmacokinetic profile applies.
Interactions
The register holds no measured interaction between faecal transplant and a cancer treatment class beyond the immunotherapy response it is being tested to improve.
Nobody having looked is not the same as nothing being there. That is what this line says and all it says.
The whole interaction list, and how to turn it into a pharmacy review request.
Find a trial instead
This is one of the few entries where the honest answer is that it is being tested properly right now, and a trial is the place to receive it.
Search ClinicalTrials.gov for recruiting studies of fecal microbiota transplantation OR FMT melanoma
A trial is the same decision with monitoring, a known preparation and a doctor who knows what else you are taking.
References
DeFilipp Z, Bloom PP, Torres Soto M, et al. Drug-resistant E. coli bacteremia transmitted by fecal microbiota transplant. New England Journal of Medicine 2019;381(21):2043-2050.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 23 note 12. The author string is abbreviated in the source that was read and has not been expanded.
United States Food and Drug Administration safety alert, March 2020, and a further alert in August 2022, concerning infections following investigational use of faecal microbiota transplant.
No persistent identifier recorded.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 23 note 13.