A pill made from human faeces could banish the symptoms of irritable bowel syndrome (IBS).
Codenamed EBX-102-02, it works by restoring a healthy balance of bacteria in the gut microbiome – the mix of bacteria, viruses and fungi in our digestive tract that play a crucial role in regulating everything from our bowel habits to immunity and mental health.
The latest results from a UK clinical trial involving 122 patients with IBS suggest taking just two doses of the drug a week apart was enough to significantly reduce debilitating symptoms including diarrhoea and constipation (IBS can involve both), stomach cramps and bloating.
Almost 60 per cent of volunteers reported a significant reduction in symptoms in the weeks and months after taking the two doses.
A larger study is planned for later this year to see if the findings can be replicated in more patients. If this is successful, the drug – the first of its kind – could become available on prescription on the NHS in the next few years.
IBS affects one in five UK adults – around 12 million. It can cause stomach cramps, bloating, nausea, wind, faecal incontinence, fatigue, diarrhoea and constipation, which can last for months.
The exact cause is not known, but it can be triggered by oversensitivity in the gut, stress and stomach infections, such as gastroenteritis. A family history of IBS also raises your risk.
Two-thirds of sufferers are women, and the hormone oestrogen has been shown to activate cells in the lining of the gut in such a way that it can bring on IBS symptoms. But it can take years for patients to be diagnosed, as doctors must first rule out serious illnesses with similar symptoms, including inflammatory bowel disease and cancer.
IBS sufferers can have debilitating symptoms including diarrhoea, constipation, stomach cramps and bloating
Clostridium difficile infection kills around 1,600 people a year in the UK
IBS is usually treated with a combination of diet and lifestyle changes (eating more fibre to combat diarrhoea, for example) and medicines such as mebeverine, an anti-spasmodic drug used to treat stomach cramps.
In recent years, small clinical trials have found that faecal transplants – in which tiny fragments of poo from a healthy donor are implanted into the gut of IBS sufferers using an endoscope (a long, flexible probe with a camera on the end) can make a big difference.
One of the most recent, published last October in the Journal of Neurogastroenterology and Motility, found that 37 out of 46 volunteers with moderate to severe IBS experienced a significant improvement in symptoms in the three months after they had a faecal transplant.
However, transplants via endoscope are labour intensive and have to be carried out by trained staff in a hospital setting.
In recent years, two UK centres – Birmingham University and Guy’s and St Thomas’ Hospital in London – have been collecting faecal donations from the public to make freeze-dried capsules to treat health problems. Each donor undergoes health screening before samples are accepted.
Dr Lindsey Edwards, a research scientist specialising in the gut microbiome and faecal transplants at King’s College London, said the initial results were ‘promising’
The capsules are then mainly used to treat Clostridium difficile infection, which kills around 1,600 people a year in the UK. However, they’re now being investigated as possible treatments for liver disease, food allergies and even anxiety.
EBX-102-02, developed by the Glasgow pharmaceutical firm EnteroBiotix, is designed to have a wide range of ‘good’ bacteria known to be beneficial for gut health – unlike over-the-counter probiotics, which tend to have a smaller selection of organisms and have not been found to improve IBS symptoms.
The treatment is regarded as a drug as it will be a registered medication – only available on prescription.
Like most oral drugs, it has a coating to protect its contents from the harsh conditions of the stomach – where acid could destroy the bacteria before they get a chance to be absorbed into the bloodstream. Most over-the-counter probiotics don’t have this coating.
Lindsey Edwards, a research scientist specialising in the gut microbiome and faecal transplants at King’s College London, said the initial results were ‘promising’, particularly the fact that symptom relief in patients on the drug seemed to last several months after just two doses.
Ms Edwards, who was formerly a consultant at EnteroBiotix but was not involved in developing the drug, said: ‘It’s genuinely exciting to see such promising results.
‘IBS significantly impairs quality of life, and current treatments often fail to deliver symptom relief. Up to 75 per cent of patients struggle with persistent symptoms. This drug has real potential.’
However, almost a third of patients given EBX-102-02 reported nausea, and one quit the trial after complaining of vomiting and headaches.
Meanwhile, a separate study by Imperial College London – which got under way in 2025 – is looking at whether faecal transplant pills can treat Crohn’s disease, a chronic condition that causes painful inflammation in the digestive tract, and leads to persistent diarrhoea, tummy pain, weight loss and exhaustion.
