This study evaluated the therapeutic efficacy of N-acetylcysteine (NAC) nano-spray in managing RIOM, with particular emphasis on mucositis severity, quality of life, and serum gastrin-17 levels.<h4>Materials and methods</h4>In this randomized clinical study, 40 oral cancer patients undergoing radiotherapy were allocated in a 1:1 ratio to receive either NAC nano-spray (n = 20) or conventional therapy (n = 20) for six weeks. Here, GAST is linked to mucositis.