FMT Safety and tolerability of frozen, capsulized autologous faecal microbiota transplantation. A randomized double blinded phase I clinical trial (Sep 2023, n=24, Clindamycin antibiotic pretreatment).

Fecal Microbiota Transplants

Michael Harrop

Active member
Jul 6, 2023

They gave Clindamycin antibiotic to healthy people for a week, then fed them their own poop (two capsules twice daily for five days). The aFMT group didn't recover any faster from the antibiotics than the placebo group.

This is an unethical experiment.



Faecal microbiota transplantation (FMT) is recommended treatment for recurrent Clostridioides difficile infection and is studied as a potential modifier of other gastrointestinal and systemic disorders. Autologous FMT limits the potential risks of donor transplant material and enables prophylactic treatment. Capsulized FMT is convenient and accessible, but safety data are lacking.


To describe safety and tolerability of capsules containing autologous FMT, compared to placebo, in healthy volunteers treated with antibiotics.


Healthy volunteers without antibiotic exposure during the past three months, that had a negative Clostridioides difficile stool sample, were recruited. Study persons donated faeces for production of capsules containing autologous microbiota. They were then given Clindamycin for seven days to disrupt the intestinal microbiota, which was followed by a two-day washout. Study persons were then randomized (1:1) to unsupervised treatment with autologous faecal matter or placebo, with two capsules twice daily for five days. A standardized questionnaire about side effects and tolerability, daily until day 28, and on days 60 and 180, was completed.


Twenty-four study persons were included, all completed the treatment. One person from the placebo and FMT groups each, were lost to follow up from days 21 and 60, respectively. No study person experienced serious side effects, but severe fatigue was reported during the antibiotic period (n = 2). Reported side effects were mild to moderate and there were no significant differences between the groups. Reported general and intestinal health improved significantly and similarly in both groups after the antibiotic treatment. Time to normalized intestinal habits were 17 and 19 days from study start in the placebo group and the FMT group, respectively (p = 0.8).


Capsulized frozen autologous faecal microbiota transplantation was safe and well tolerated but did not affect time to normalized intestinal habits compared to placebo.

Reported adverse events were primarily minor and transient and there were no significant differences between those receiving placebo or auto-FMTA

These quotes seem to be conflicting:
Treatment with clindamycin was associated with significantly lower scores of general health and a trend towards worse intestinal health compared to treatment with auto-FMT or placebo and compared to the follow-up period
Reported general and intestinal health improved significantly and similarly in both groups after the antibiotic treatment

If the accurate result was that people in both groups of healthy subjects said their health improved after the antibiotics, that's not uncommon. Antibiotics often have short-term benefits and long-term detriments.
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