People with bowel ulcers could soon be topping up their "friendly" bacteria to beat their illness.
The scientists say further research is needed
Scientists in Scotland have discovered that people with ulcerative colitis have lower levels of a specific type of friendly bacteria.
They have now developed a treatment to boost levels of this bacteria.
Tests on patients suggest it can dramatically reduce the pain, diarrhoea, fatigue and weight loss associated with the condition.
Ulcerative colitis affects 50,000 people in the UK. The disease causes ulcers in the lining of the large bowel.
At the moment, patients are given anti-inflammatory drugs or steroids to try to reduce their symptoms. However, these can have unpleasant side-effects.
If patients do not respond to drugs they may have to have surgery.
Professor George Macfarlane and colleagues at the University of Dundee say their discovery could transform the treatment of these patients.
Over the past two years, they have given patients with the disease a drug cocktail to try to encourage the growth of a specific type of friendly bacteria - a so-called probiotic. They are not naming the bacteria for commercial reasons.
Patients took a pill containing freeze-dried bacteria and a sachet drink containing carbohydrates before breakfast and after their evening meal every day for four weeks. This combination is known as a synbiotic.
They said the treatment reduced inflammation in the bowel and reduced the pain and discomfort experienced by patients. There were also no side-effects.
"The trial results show that participants receiving the synbiotic stopped experiencing pain, diarrhoea and other symptoms commonly associated with the disease," said Professor Macfarlane.
"This meant that they could go about their daily lives without worrying about the symptoms that makes living with the disease a struggle."
He added: "This is an important development in the search for an effective treatment for ulcerative colitis."
The researchers are now planning to test the treatment on a larger number of patients.
The National Association for Colitis and Crohn's Disease said a growing number of scientists are carrying out research in this area.
"More and more people are becoming interested in the potential benefits of probiotics," said Helen Terry, its information services manager.
"It's looking like a promising area for further research."