This thesis examines the antifungal potential of capsaicin derivatives (OM94, OM97, OM103, OM106, etc.) against Fusarium graminearum, a pathogen responsible for Fusarium head blight (FHB) and mycotoxin contamination in cereals. The study targets essential fungal genes (PKS4, PKS12, Tri5, FUM1, FUM7) involved in toxin biosynthesis, using qPCR to analyse gene expression changes under capsaicin treatment. By incorporating capsaicin compounds into PDA media at varying concentrations (5–200 mg/L), the research aims to identify whether these natural compounds can suppress virulence genes or alter metabolic pathways. The work bridges gaps in understanding plant-derived antifungal agents and their molecular mechanisms against F. graminearum. If proven effective, capsaicin could offer a sustainable alternative to chemical fungicides, reducing mycotoxin risks in food chains. The thesis underscores the need for innovative strategies to combat crop diseases while minimising environmental and health impacts.