Saponins are secondary metabolites with triterpene structure that first were identified inplants and later their existence was confirmed in some marine animals including seacucumbers. These compounds have a wide spectrum of pharmaceutical and health effects.This study was conducted to evaluate the cytotoxicity and anti-inflammatory effects ofHolothuria leucospilota sea cucumber saponin on Human lung adenocarcinoma epithelialcell line (A549). The A549 cells were cultured, seeded and exposed with differentconcentrations of saponin (0.12, 0.25, 0. 5 and 1 Âμg/ml). Evaluation of antiproliferative effectof saponin against cancer cells was performed by MTT procedure after 24, 48 and 72 h oftreatment. Alterations in the expression level of IL-1Î² were assessed after 48 h of treatment.For this purpose, total RNA was extracted and cDNA was synthesized by appropriate kitsand the expression level of IL-1Î² were evaluated by Real-time- PCR assay. MTT assayshowed that the cell growth was inhibited by increasing the concentration of saponin. IC50for 24, 48 and 72 h were about 0.7, 0.5 and 0.4 Âμg/ml respectively. The Real-time- PCRanalysis showed that the expression of IL-1Î² was reduced as a pro-inflammatory genes. Theexpression of this gene was reduced from 6.56 in untreated cells to 1.48 in treated cells with1 Âμg/ml of saponin. Taken together, this summary offers evidences for the antiproliferativeand anti-inflammatory properties of saponin derived sea cucumber and suggests that saponincan be used as an anticancer and anti-inflammatory agent.