The BBC reports Gut bugs 'help prevent allergies' "Bacteria that naturally live inside our digestive system can help prevent allergies and may become a source of treatment, say US researchers."
The research group performed experiments on mice brought up in perfectly sterile environments and had no bacteria in their gut.
These animals had a strong immune response to peanut - an allergy that can be deadly in some people.
The team then investigated whether adding different bacteria to the digestive tract of the animals had any effect.
Only the Clostridia group of bacteria - which includes some disease causing species such as C. difficile - could prevent the allergic reaction.