In this study, we aimed to develop foods with antitumor and complementary effects against cisplatin (CDDP)-resistant bladder cancer. UMUC3, a human bladder cancer cell line was exposed to CDDP and cultured over a prolonged period to prepare UMUC3-CR, a CDDP-resistant subline. Androgen receptor mRNA expression was high in the UMUC3-CR subline. Genistein and vitamin C suppressed UMUC3-CR tumor growth. Additionally, the liberal intake of cheese in parental cell UMUC3-transplanted mice was associated with prolonged survival. Therefore, we created konjac jelly (KIK300) containing soy milk, cheese, and vitamin C as the main ingredients. Liberal administration of KIK300 to UMUC3-CR-transplanted mice suppressed tumor growth and reduced vascular endothelial growth factor mRNA expression. Furthermore, we observed no weight loss in the animals, their skin condition improved, and exercise capacity was improved. In conclusion, this study suggests that KIK300 may show antitumor and complementary effects on CDDP-resistant bladder cancer.