Background: Cisplatin, while potent against cancer, causes significant nephrotoxicity and hepatotoxicity. Objective: To investigate the protective effects of curcumin and flaxseed oil against cisplatin-induced toxicity. Materials and Methods: Animal models (rats) were divided into four groups: a control group, a cisplatin-alone group (single dose of 7.5 mg/kg i.p. on day six), a curcumin group, and a flaxseed oil group (0.1 ml/1 kg orally for ten days with a cisplatin dose on day six). Liver and kidney functions were assessed by measuring serum (alanine transaminase) ALT, aspartate aminotransferase (AST), urea, and creatinine levels. Protein metabolism was evaluated by measuring total protein, albumin, and globulin levels, and the albumin/globulin ratio, followed by histological examination of liver and kidney biopsies. Results: Cisplatin significantly increased ALT, AST, urea, and creatinine levels indicating severe liver and kidney damage (p < 0.001). It also decreased total protein, albumin, and globulin levels, impairing protein metabolism (p < 0.001). Co-administration of curcumin or flaxseed with cisplatin significantly reduced ALT, AST, urea, and creatinine levels, while improving total protein, albumin, and globulin levels and improved histological results compared to the cisplatin-alone group. Conclusion: Curcumin and flaxseed effectively mitigated cisplatin-induced hepatotoxicity, nephrotoxicity, and disturbances in protein metabolism. Thus, they could be potential adjuvant therapies in cisplatin chemotherapy to reduce its side effects.