INTRODUCTION: Cisplatin is a widely used anti-cancer drug that is commonly administered for the treatment of various cancers. However, nephrotoxicity is the most important side effect of this drug which limits its use. This study aimed to investigate the protective effect of Cystone against nephrotoxicity induced by Cisplatin in patients with cancer. METHODS: This pilot clinical trial study was conducted on 43 cancer patients treated with Cisplatin (75 mg/m2 for a period of six months). The subjects were divided into treatment group (receiving Cystone, two per 8 hours; = 21) and control group ( = 22). The two groups were compared with each other in terms of demographic and laboratory variables. RESULTS: In the intervention group receiving Cystone, serum creatinine-based GFR level ( = 0.453) and 24-hour urine creatinine-based GFR level ( = 0.397) did not change significantly during the studied period, but in the control group, serum creatinine-based GFR level ( = 0.013) and 24-hour urine creatinine-based GFR level ( = 0.016) significantly changed. Serum creatinine-based GFR level increased by 2.3 units in the intervention group and 10.5 units in the control group ( = 0.005) in the six months of the study. At the end of the sixth month, 24-hour urine creatinine-based GFR level increased by 2.2 units in the intervention group and 0.8 unit in the control group ( = 0.008). CONCLUSIONS: The use of Cystone resulted in more stable kidney function indices in the intervention group, as compared with the control group. Therefore, Cystone seems to have a protective effect against nephrotoxicity induced by Cisplatin in cancer patients.