Diabetes patients could be able to receive insulin via a nasal spray using yeast, scientists believe.
More than 1.7m people in England have diabetes
Leeds University researchers found the fungus, traditionally used to make beer and bread, opened nasal cells to allow insulin to pass through nose tissue.
They hope it will allow a spray to be developed to replace injections.
A Diabetes UK spokeswoman said it would welcome "any safe, effective advances which make the treatment of diabetes easier and more comfortable".
Getting insulin into the bloodstream through the nose is tricky because the layers of tissue lining the nose, known as the nasal mucosa, can block the molecule.
But in preliminary research, the scientists found that yeast, which is non-toxic, opened up the tight junctions between nasal cells.
Lead researcher Emily Fuller said: "Transport of large molecules, such as insulin, through the nasal mucosa is limited because of the tight structure of the cell layer which forms an impenetrable barrier.
"Our laboratory results show that yeast cells successfully enhanced the penetration of insulin."
The team, which presented its findings at the British Pharmaceutical Conference in Manchester, said more research was needed.
Researchers also said they were looking at yeast's properties as a drug delivery system.
They said it might be possible to encapsulate active drugs inside yeast cells to protect them until they get to the site of action.
Zoe Harrison, care advisor at Diabetes UK, said: "In the UK, there are around 700,000 people with diabetes whose only treatment option is daily insulin injections.
"Although this nasal therapy is in its very early stages, Diabetes UK welcomes any safe, effective advances which make the treatment of diabetes easier and more comfortable.
"We will await the results of the first clinical trials with interest."