This study compared two antifungal medications (nystatin and amphotericin B) for treating oral yeast infections in cancer patients receiving head-and-neck radiotherapy. Researchers tested how well each drug worked against different Candida yeast species before and during radiation treatment. The results showed that nystatin was more effective than amphotericin B at killing the yeasts, with nystatin working against all yeast species tested, while amphotericin B had reduced effectiveness against some Candida albicans strains.