The title says it. Poo soup.

Poo soup something that can help treat disease in many animals, including horses and even humans. As a vet it’s one of my favourite things to talk about, and as a scientist I think it’s a great demonstration of the importance of the microbiome (the collection of nasty and nice micro-organisms that share our body).

Let me explain. We are full of bacteria, or rather our intestines are. Imagine a crowded gig – Cradle of Filth or One Direction if you like, with people packed together in an enclosed space. In many ways, intestines are like a really smelly One Direction concert, with bacteria instead of people. Having lots of normal bacteria makes it difficult for the harmful disease-causing ones to get in.

One problem that we face is when we use antibiotics. We use these medications under special circumstances to treat bacterial infections. But at the same time they can clear your gut of all your protective bacteria, and this allows the harmful ones to set up shop.

And one unfortunate side effect that can sometimes happen is a nasty infection of something called Clostridium difficile (it even sounds horrible). Clostrdium is a bacteria that can be found in the intestines of healthy people, but in small numbers. When the protective good bacteria are wiped out by antibiotics, Clostridium can multiply to fill up the vacant space. It then produces toxins, which cause really terrible diarrhoea, and can actually be fatal to those who are particularly vulnerable. Both humans and horses alike are susceptible to this problem.

One way of treating this is just to use more antibiotics, but this can be tricky, as there’s a risk that more antibiotics can just make the problem worse. Add to that the growing problem of antibacterial resistance, and this option looks even less attractive.

But in horses, another way of treating bacterial overgrowth is to use poo soup; where we take poo from a healthy horse, and donate it to the sick horse. You might be wondering: how does one make poo soup? It’s very scientific. You take poo, mix it with warm water in a bucket, and give it to the sick horse via a tube. The healthy poo will be full of communities of normal, disease preventing bacteria, which will overcrowd and push out the Clostridium bacteria. Here’s a very recent review about it in horses (paywalled, but contact me if you want to know more).

Horse poo! Perfect for soup. Credit: CC-BY-3.0


This story gets even better.

This is also an effective way of treating the same condition in humans. Only in people, it’s more sensibly called a faecal transplant (although in ancient China, it was referred to as ‘yellow tea’). In fact, a faecal transplant can be dramatically more effective at treating Clostridium infection than antibiotics. In one famous study, researchers saw a clinical cure in 94% of patients that had faecal transplants, vs. the 27% of people treated with antibiotics. In fact, the study was halted earlier than planned, so that all the participants could receive faecal transplants.

This area of medicine has come along so far now, that there’s even a poo bank from where you can get your faecal transplant. Here the donated and medically screened faeces can even be refined to point that they can be safely and effectively packed into capsules. This avoids the need for traditional methods of delivery, such as enemas and nasoduodenal tubes – a huge advantage, considering that many people in need of this treatment are already chronically (and often painfully) ill.

So if you’re a horse, you still have to rely on the soup. But if you’re a human being you can just take a pill. Either way – bottoms up.

*This blog post is lifted almost straight from my Famelab talk in Cambridge a few weeks ago. Three minutes onstage to talk science – well worth a go if you’re interested next year!*

Chris, @thebadlizard