Eat sh*t – the many wonders of faecal transplants

Image Credit: Orin Zebest via Flickr.

A faecal microbiota transplant (FMT) is the process by which a healthy stool sample is administered to a recipient in order to restore the gut microflora, encouraging the growth of ‘good’ bacteria. FMT was originally carried out by liquefying donor material and administered via faecal enema or nasointestinal tube however recent studies have shown that FMT can be safely and effectively administered in the form of a frozen poop capsule. Tasty. The US is home to the world’s first ‘public stool bank’, OpenBiome, which stores screened and frozen samples donated specifically for FMT.

So why on earth would anybody need a faecal transplant? The human body is home to roughly 10 times more bacteria than human cells, the majority of which reside in the gut. This microbiota is carefully balanced, and works in harmony with our immune, nervous and digestive systems. Many of these bacteria play a key role in vitamin production and energy metabolism. Imbalances in the gut bacteria have been implicated in some autoimmune diseases and can even alter the production of essential neurotransmitters. Reduced microbial diversity has also been shown to aggravate obesity1. Bacteria and their by-products can modulate brain function and behaviour via the gut-brain axis. This allows two-way communication between the bacteria of the digestive system and the central nervous system (CNS). With this in mind, it would make sense that rebalancing the gut microbiome could improve conditions which affect the nervous system.

Faecal transplants are not a new concept to theGIST, so if you’d like to read more about FMT in the treatment of obesity and C. difficile infections then check out Brett Johnson’s article here:

The popularity of FMT is on the rise and studies show that stool transplants can be used to treat a widespread range of diseases, not just those affecting the gut such as Inflammatory Bowel Syndrome. It is a relatively new therapeutic strategy in the treatment of CNS disorders in which patients can display altered gut flora, for example multiple sclerosis, Parkinson’s disease (PD) and even schizophrenia2. Parkinson’s is a complex disease and any slight improvement in symptoms can make a huge difference to the lives of sufferers. It is common for constipation to occur very early on in PD and this may even be a risk factor in disease development, with a neurotoxin found in the gut flora of patients thought to exacerbate neurological symptoms. Evidence suggests that regular bowel transit can in fact help to reduce these more severe symptoms of the disease including the characteristic involuntary tremors. Case studies have shown that FMT is effective in improving the balance of ‘good bacteria’ in the microbiota and successfully improving not just constipation (which has been difficult to treat in the past) but also noticeably improving disease symptoms as a whole 3.

The gut bacteria-brain connection has also come to the forefront of autism research within recent years. Research has shown that many children with autism show abnormalities in their gut microbiota, with some individuals suffering from regular gastrointestinal disturbances like bloating and diarrhoea. Stool samples from autistic children have been seen to have reduced diversity of bacteria compared to the gut flora of normal children and also showed altered concentrations of metabolites which are involved in neurotransmitter synthesis. Some research groups have even gone so far as to link certain severe symptoms of autism to the higher prevalence of specific bacterial strains (including Clostridia) 4. The concept that the bacterial disturbances seen in autism may not just be a symptom, but could possibly contribute to the illnesses development is a controversial one, however there is some evidence to suggest that altering the gut microbiota (mainly with antibiotic treatment) can have a positive impact on behavioural symptoms. This data suggests that FMT may have great therapeutic potential for improving the symptoms of autism by increasing bacterial diversity.

FMT has provided a simple, drug-free treatment for many conditions affecting the digestive system, and results look promising in the treatment of other non-GI conditions. Many studies investigating faecal microbiota transplants for the treatment of neurological diseases are still in the early stages, it will be interesting to see if the results are so positive in larger clinical trials. The relationship between gut, brain and microbiota is a complex one which is still not fully understood, but further research may reveal yet more ways to exploit this connection for novel disease treatments. The apparent success of FMT in treating Parkinson’s disease and autism has also raised questions about whether the microbiota may play a role in the origin of disease, a controversial topic but one that may gain ground with further research. Even if bacteria doesn’t contribute to disease development, it certainly seems to affect symptom profiles and FMT may improve the lives of many patients. Having said that, I think some more thought could go into improving methods of administration… poo pills? I think I’d rather have an enema.


This article was specialist edited by Catriona Thompson and copy edited by Jessica Marie Bownes.



  1. See here.
  2. More information here.
  3. See here.
  4. See here.

You may also like...

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.