Cranberry juice may help to combat viruses that cause gut disorders, research suggests.
Cranberries help reduce urinary infection
Drinking the juice is already recommended as a way to cut the risk of urinary tract infections.
Scientists found adding cranberry juice to intestinal viruses in laboratory conditions blocked their ability to infect intestinal cells.
The research, by St Francis College in New York, was presented to the American Society for Microbiology.
Intestinal viral infections are responsible for thousands of infant deaths around the world each year, mainly in developing countries.
The St Francis team focused on an intestinal virus carried by monkeys called SA-11, and several similar viruses carried by goats.
After the viruses were treated with cranberry juice they were unable to infect intestinal cells in the usual way.
The researchers believe cranberry juice might destroy or modify receptor sites on the host cells to which viruses usually bind.
Alternatively, it might damage the protein docking mechanism of the virus itself.
Researcher Dr Steven Lipson told the BBC News website: "Cranberry juice seems to have an effect on the replication cycle of the virus at an early stage so that it fails to penetrate the host cell."
Dr Lipson said the key might be chemical components of the juice called flavenoids and tannins, both of which have previously been shown to have an anti-bacterial effect.
However, the researchers say further research is needed to determine whether drinking cranberry juice alone would be enough to reduce the risk of intestinal infections.
Dr Alastair Forbes, a spokesman for the digestive disorders charity Core, said the study highlighted an interesting example of a potential "functional food" - a food that has a beneficial effect beyond its nutritional impact.
"Cranberry juice is already idenitifed in this way for its proven benefits on urinary tract infections and cystitis.
"The postulated impact on gastrointestinal viruses is to be welcomed if this can be confirmed in humans.
"Gastrointestinal viruses are anyway the commonest cause of gastroenteritis in the UK.
"Knowing that cranberry juice could prevent some of these episodes or reduce their impact would be of real value."
However, Dr Forbes said large clinical trials would be needed to confirm any positive effect.
The research was part-funded by the Cranberry Institute.