My detailed experiences & lessons from 13+ different FMT donors (Jun 2018- )

Michael Harrop

Active member
Jul 6, 2023
Fairly long so probably won't be able to review it all in one sitting/day.

Originally posted on 21 Jun 2018 (26 comments) after 8 donors. Here is the summary that hasn't changed much since then:

High-quality donors are likely a panacea but most official sources of FMT are using low-quality donors and horribly/dangerously inadequate screening/selection. Low-quality donors can be dangerous, and mostly ineffective. Every donor is unique. High-quality donors are similar in most aspects. The FMT screening questionnaire in the wiki is a vital screening tool.

I did put some bullet points in the beginning of the document. I'll quote that part here:
A few takeaways:
  • There seems to be major signaling along the entire intestine. Stuff that seems upper GI related can be impacted via colon FMT.
  • Neither Xifaxan or Metronidazole made low quality donors more effective.
  • Flagyl very effective/helpful once it makes it through the whole colon, yet using it via enema does nothing. Major differences between IV, oral, or enema flagyl.
  • Long term (months) FMT is likely needed for more complex conditions. Yet some things (bile acid diarrhea) seem easily fixable via 1-2 FMTs with the right donor.
  • Doing the retention enema right after a BM seemed as, if not more, effective than doing a complete colon cleanse via inducing diarrhea. Though the donor stool quality was not consistent. I made sure to lie in inclined positions to get it to flow through the whole colon. Inducing diarrhea itself though seemed to possibly have some impacts, such as improvements to skin, and possibly impacting some pathways and thus changing location of some problems and possibly helping flush some others through. Some support: Transient Osmotic Perturbation Causes Long-Term Alteration to the Gut Microbiota (2018): But one of the agents I used for inducing diarrhea (h202) probably played a primary role.
  • Pathways - it seems like often things don't get fixed but rather the problem gets moved to another pathway/location. Arthritis, some rough skin patches, unique BOs, heart problems vs head problems, red dots, are a few examples. Possibly related to this? "A newly discovered network of fluid-filled channels in the human body may be a previously-unknown organ, and it seems to help transport cancer cells around the body" (2018)
  • Via enema seemed more effective with certain donors. But I've heard feedback from other people that the oral route seemed more effective for them. I started doing both when possible.
  • Small amounts (less than 1 capsule) seemed as effective, if not more so, than larger amounts (2-6oz).
  • Nearly anything wrong with the donor can be transferred.
  • Nearly every donor had unique effects, but 1 and 4 seemed very similar in questionnaire, stool type and effects.
  • 0 lifetime antimicrobial use might be an important factor. Perhaps due to long-term damage, or perhaps due to a healthy/disease resistant gut microbiome never needing antimicrobials.
  • It seems very clear to me that high quality donors have something very important, that stimulates an immune system response, that low quality donors completely lack. So combining multiple low quality donors cannot equate to one high quality donor (what Taymount seems to be trying to do). I have a feeling this very important factor is severely damaged by antimicrobials. Maybe phages, maybe some immune system component.
  • Since stool testing (conventional & commercial 16s) is extremely limited you have to rely on an in-depth questionnaire, but even well-meaning people omit, forget, or downplay certain things.
  • Donors seem to majorly misjudge their stools. That plus the fact that intermittent soft stools seem to be dangerous means that you probably want to get multiple samples from a person over 2-3 days straight to judge the stool for yourself before using any of it.
  • I had no idea how important stool type/consistency was coming into this, but it seems high quality donors have identical stools, while low quality donor's stools are heterogeneous, thus it's one of the major ways to judge stool quality. This is based on my own experiences, and from experiences from numerous other people. And this Anna Karenina hypothesis supports this: This 2017 study saying otherwise is only for c.diff (which requires much less strict donor criteria): And it's quite likely that study completely lacked high quality donors (due to severe deficits in OpenBiome's donor selection), so they were only comparing average/low quality donors with each other. Also I believe it is a matter of "the highest quality donors all have type 3 stools, but not every donor with type 3 stool is high quality". At this point I would nearly bet my life on every single person in the "healthy" category/list above consistently having type 3 stools.
  • I think that continued FMTs (weeks/months) with donors 1 or 4 could result in sustained improvements if not cure. But they both made themselves unavailable. FMT from these two donors felt like taking 1 antibiotic pill when you're supposed to take 3x/day for 2 weeks. This (along with prebiotic experience below) might implicate phages as one of the most important components of FMT.
  • Prebiotics and other whole foods that harmed me prior to FMT also harmed me during & after FMT. At best, they had no impact. I do not think you should/can introduce these until you're pretty much in complete recovery. My experience with this says it is misguided to try and feed the new bacteria from the FMT. You shouldn't have to force these, but rather the right microbes from the right donor will allow you to reintroduce certain foods: + "diet" section of wiki.
Based on my experience & knowledge it seems soft stools are from one or more of:
  1. A low quality gut microbiome that lacks certain microbes needed in the digestion of certain foods.
  2. A pathogen that feeds off certain food items (iron for example:, and thus causes soft stools & other problems when eating those foods.
  3. Temporary upset from either mild food poisoning or poor hygiene/sanitary practices.
Included required info?
  1. Yes