ABSTRACT The aim of this study was to investigate the effect of capsaicin and ethanolic Capsicum extracts on B104 neuroblastoma cells as a potential anticancer agent. Additionally, this study also aims to examine the influence of co-extracted bioactive compounds (vitamin E, vitamin C and quercetin) in Capsicum fruit extracts on the cytotoxic effects of capsaicin in neuroblastoma cells. MTT and LDH assays were used to determine viability and cell death in B104 neuroblastoma cells. Antioxidative properties of capsaicin, vitamin E, vitamin C and quercetin were estimated by means of cyclic and square wave voltammetry. There was a significant cytotoxicity of capsaicin (100 µmol/l) after 24 h incubation and for capsaicin (250 µmol/l), even when cells are treated for 1 h. On the other hand, ethanolic Capsicum extracts which contained capsaicin (0.5–2.1 mmol/l) did not show any cytotoxic effect. We suggest therefore, that other co-extracted compounds within the ethanolic extracts interact antagonistic with the cytotoxic effect of capsaicin and their interactions should be further investigated. Our results indicate that capsaicin in high concentration induces cytotoxic effects in a dose dependent manner, but other bioactive compounds present in Capsicum fruits prevent the cytotoxic effects of the extracts on neuroblastoma cells.