Objective: The objective of this study was to design an effective topical treatment for oral mucositis.Methods: Poly-(DL-lactide-co-glycolide) (PLGA) nanoparticles (NPs) and Poloxamer407 (PLX)/Hydroxy propyl methyl cellulose (HPMC) hydrogel matrix (HG) were used as combined carriers for benzydamine HCL (BNZ). BNZ loaded PLGA nanoparticles were assessed for their particle size, PDI, zeta potential and entrapment efficiency. Scanning electron microscopy, thermosensitivity study, mucoadhesion study, in vitro release and in vivo investigation were used to characterize the combined BZN loaded PLGA NPs HG.Results: Negatively charged NPs with an average diameter of 139±4.92 nm were incorporated into PLX/HPMC HG bases. The gelation temperature of BZN-PLGA-NPs-HGs ranged between 31°C and 36.5°C. When diluted with saliva simulated fluid, BZN-PLGA-NPs-HGs preserved their gelation properties. Mucoadhesion was found lower for formulations prepared with PLX without HPMC. An increase in the concentrations of PLX from 10 to 30% resulted in an increase in adhesion. Both PLGA-NPs and PLGA-NPs-HG provided a biphasic drug release profile while BZN-HG provided monophasic zero order release pattern. The in vivo study showed that animal groups treated with BZN-HG and BZN-PLGA-NPs-HG showed a significantly higher reduction percentage in ulcer surface area compared to those treated with BZN-PLGA-NPs. BZN-PLGA-NPs-HG group needed 10 d of treatment to complete healing versus 16 d, 14 d and 12 d for the complete healing of groups with no treatment, treated with BZN-PLGA-NPs and treated with BZN-HG, respectively.Conclusion: BZN-PLGA-NPs-HG could represent a promising mean for the effective treatment of oral mucositis induced by cancer therapy.