Couch grass is used to clean the urinary tract during infections due to its diuretic and antimicrobial effects. The aim of this study was to investigate the possible protective or therapeutic effects of couch grass on gentamycin-induced nephrotoxicity in rats. Four groups of 10 rats were formed in the study. First group, Control: Rats were fed with standard rat feed and water. Second group (couch grass): 3 gr/ L couch grass was added to the drinking water of rats for 7 days. The third group (gentamicin): Gentamicin 80 mg/ kg/ day/ i.p. was given for 7 days. The fourth group (gentamicin + couch grass): Gentamicin 80 mg/ kg/ day/ i.p. and 3 g / L couch grass was added to drinking water for 7 days. One week after the experimental application, blood samples were taken and serum was separated. Albumin, BUN, creatinine, urea, GGT, ALP, Na, Cl and K levels were determined in autoanalyzer. Cystatin C was measured by ELISA. Serum BUN, creatinine, urea, Na, K levels were highest in the gentamicin group. Na, K and cystatin C levels differences between groups were not statistically significant. The increase in BUN, urea and creatinine after gentamicin administration was statistically significant (p<0.05). The use of gentamycin and couch grass caused BUN, urea and creatinine levels to decrease. The difference between the groups was found to be statistically significant (p<0.05). The administration of gentamycin and couch grass decreased cystatin C levels, statistical significance was found between the groups (p<0.05). No statistically significant difference was found between the groups in albumin, Cl, GGT, ALP levels (p>0.05). As result, positive changes in serum parameters of gentamycin induced nephrotoxicity when couch grass were given, showed that couch grass had a kidney protective effect and decreased nephrotoxic damage.