Yoghurts containing "friendly bacteria" are being used as part of a trial to cut the risk of patients developing superbugs at a Sussex hospital trust.
The trust said it would be evaluating the cases of C.diff
Free pots of probiotic yoghurt are being handed out at the Royal Sussex County Hospital in Brighton and the Princess Royal in Haywards Heath.
They are being given to patients on wards where there have been higher cases of Clostridium difficile.
The trust said evidence suggested the yoghurt might cut the risk of C.diff.
Brighton and Sussex University Hospitals NHS Trust medical director Matthew Fletcher said: "We are providing Actimel probiotic yoghurt to patients on the wards where we have previously had more cases of C.diff.
"There is some evidence to suggest that using these probiotics may reduce a patient's risk of C.diff and we will be evaluating the difference this has made to the number of cases."
In January scientists said they had hard evidence that foods containing "friendly bacteria" did have a tangible effect on the body.
The journal Molecular Systems Biology reported that mice fed probiotic drinks had different levels of key chemicals in their blood and urine.
The Imperial College London research - which was part-funded by food giant Nestle - also suggested they could change fat digestion but dieticians said this would work only for relatively small numbers of people.
Probiotics, meaning "for life", are products that contain live strains of bacteria incorporated into yoghurts, fruit juices or freeze-dried powders, which boost levels of the friendly bacteria in the gut.