Nigella sativa seed is widely used as general tonic , it was suggested to have a general protective roles. Twenty four white male albino rats were divided into four equal groups. The first group was exposed to sham operation and received saline through an oro-gastric tube for 15 consecutive days and kept as control. The other groups were subjected to unilateral nephroectomy. The second group was given suspension of crushed seeds of Nigella sativa , 2gm / kg B.W. orally daily for 15 consecutive days. The third group was injected intraperitoneally (i.p.) by gentamicin in a dose of 30 mg/kg B.W. daily for the same period. The fourth group was injected (i.p) by 30 mg/kg B.W. gentamicin i.p., in compination with 2gm /kg B.W. suspension of crushed seed of Nigella sativa orally daily for the same period. Changes in blood pressure, heart rate, blood urea and serum creatinine were recorded. The histopathologicial changes in kidneys were also demonstrated. The results of this study , revealed that, gentamicin alone showed a significant increase in blood pressure, blood urea, and serum creatinine, there is no significant changes in the group given Nigella sativa alone. On the other hand, insignificant changes were recorded in the same parameters, in the group given gentamicin in combination with suspension of crushed seeds of Nigella sativa. Histpathological studies of the kidney, showed tubular degeneration, tubular necrosis, interstitial haemorrhage and basement membrane distortion with gentamicin. On the other hand no histopathological changes were recorded in gentamicin and Nigella sativa treated group. These changes supported our findings. These results suggested that Nigella sativa seeds and their constituents did not produce deleterous effects on kidney tissues and function, but prevented the nephrotoxic manifestations of gentamicin.