In this study, Al2O3, CuO, and TiO2 nanoparticles (NPs) were individually administered to 60 mature female rats via oral gavage (0, 0.5, 5, and 50 mg/kg b. w. per day) for 14 days and then responses of ATPases in the erythrocytes, total oxidant status (TOS), total antioxidant status (TAS), and liver enzyme (alkaline phosphatase, ALP; alanine transaminase, ALT; aspartate transaminase, AST) levels in the serum were determined. There were sharp decreases in Na, K-ATPase activity in the erythrocytes following NP exposures. All doses of CuO caused significant (P < 0.05) inhibitions in Na, K-ATPase activity (up to 94%), while only higher doses of Al2O3 and TiO2 inhibited (76%-80%) the activity of Na, K-ATPase. Oppositely, the activities of Ca-ATPase (up to 274%) and Mg-ATPase (up to 290%) increased significantly following TiO2 exposures. TOS levels significantly increased following Al2O3 (167%) and CuO (240%) exposures, though TAS levels did not change significantly in any of the exposure groups. The levels of ALP, AST, and ALT increased following NP administrations. Ti-NP increased the levels of all liver enzymes in the serum (up to 84%), while Al-NP (58%) and CuNP (43%) increased only ALP levels. The present study demonstrated evidence of the toxic effects of NPs, as they altered the measured parameters in the blood, and suggests further research to better understand the environmental fate of NPs.