In developed countries, chronic rhinosinusitis with nasal polyps is one of the diseases that diminish patients' quality of life most significantly. Treatment of that often incurable disease is based on the steroids and surgery in patients who had failed thorough conservative management. It appears that the introduction of new treatment agents suppressing inflammation process and inhibiting cells' proliferation would be a valuable therapeutic option. The aim of the present study was to evaluate the in vitro effect of genistein and phytic acid on the viability and growth rate of fibroblasts derived from nasal polyps. Cells were incubated with various concentrations of genistein (5-500 μM) and phytic acid (100-20,000 μM). After 72 h incubation, cells survivability and cells' growth rate were estimated by combination of WST-1 and LDH methods. QRT-PCR technique was used to determine the expression of histone H3, BCL-2, BAX and P53 genes. Caspase-8 and -9 expressions were evaluated by ELISA assay. Genistein and phytic acid significantly and in dose-specific manner decreased nasal polyps fibroblasts survivability and growth rate. Both agents in similar way decreased cell proliferation as measured by the expression of histone H3. They induce apoptotic machinery by modulating the expression of BCL-2, BAX and caspase-8 activity. Genistein and phytic acid have significant potential for a therapeutic role in the treatment of chronic rhinosinusitis.