It is well known that dromedary camels are adapted to the harsh condition of arid and semi-arid zone. Previous studies showed its sensitivity to mineral imbalance, selenium (Se) is an essential trace elements for animal nutrition that plays a vital role in physiologic processes. Selenium deficiency in dromedaries is widespread; many cases of white muscle disease have been confirmed. For prevention and treatment as well farmers supplement with selenium, the requirements of dromedaries in selenium are extrapolated from those of other species, but excess consumption of selenium can result in selenium intoxication. No references on selenium toxicity in camels were reported. The objective of the study reported here was to investigate the effect of excess selenium (sodium selenite) supplementation (8, 12 and 16mg/day) on serum selenium level, glutathione peroxidase activity (GSH-Px), toxicity symptoms and histopathology findings. Selenium concentrations in serum increased significantly in treated groups with an average value of 321, 23 ± 140, 5; 443, 18± 231, 06 and 298, 04 ± 212, 13 ng/ml. The glutathione peroxidase activity varied between 26, 85 and 174, 16 IU/gHb. Serum selenium concentration was highly correlated with GH-Px (r = 0.70; P< 0.001). Remarkable toxicity symptoms occurred within 2 weeks of supplementation. Degenerative changes were observed in kidney, heart, liver and muscles. (Texte intégral)