Abstract: This study assessed the effect of oral administration of Costus afer leaves’ juice (CALJ) on the functional integrity of the renal tissues in rats orally exposed to nitrocellulose thinner (NCT). Three groups of six rats each, were orally administered distilled water, NCT (30.0 mg kg-1 b.wt.) and NCT (30.0 mg kg-1 b.wt.) in combination with 600 mg kg-1 b.wt. of CALJ (one hour before NCT administration), respectively for 28 days. The animals were sacrificed after 12 h fast, on the 29th day of the experiment, blood collected through cardiac puncture for serum urea, Blood Urea Nitrogen (BUN), uric acid, creatinine, kidneys for renal tissues malondialdehyde (MDA), Glutathione Peroxidase (GPx) and Superoxide Dismutase (SOD) activities determination. The results showed that NCT caused a significant (p<0.05) increase in serum urea, BUN, uric acid, creatinine and renal tissue MDA levels, as well as decrease in renal tissue GPx and SOD activities, compared to control group. These results indicated that NCT’s constituents and their metabolites are nephrotoxic. However, it was observed that administration of CALJ protected the renal tissues against the NCT-induced nephrotoxicity, as indicated by the restoration of serum urea, BUN, uric acid and creatinine levels, as well as renal tissue MDA, GPx and SOD activities to the control range. Also the tubular epithelial necrosis and atrophy of the glomeruli, observed to be associated with exposure to NCT were restored to normal on treatment with CALJ. This study strongly suggested that CALJ’s constituents possess a protective effect against NCT-induced renal tissues damage and reflected the beneficial role of Costus afer in the treatment of various clinical disorders.