ZnO nanoparticles (NPs) are widely used in industrial and consumer products. Thus, understanding their interaction with biological systems is the key for their safe application. The aim of present study was to evaluate the toxicological effects on the intestine of common carp, Cyprinus carpio, after dietary exposure to ZnO NPs. To assess the toxicity of ZnO NPs and of their toxic mechanism to gastrointestinal tract, we applied label free protein quantification on carp intestine considering the fact that fish are on the top of food chain in aquatic ecosystems. Even though carp and zebrafish do not have five intestinal segments like mammals (Brugman, 2016), previous studies have revealed that intestinal anatomy and architecture in cyprinid teleost fish is closely related to mammals with functional homology (Curry, 1939). Therefore, the findings can also provide beneficial information to understand the mechanisms underlying NPs toxicity in mammals.