The use of plants for the treatment of various diseases has been common since ancient times, and plant products are still used as the main or auxiliary treatment for many diseases. Plants have different compounds with different effects that can be used to treat diseases after identifying and purifying therapeutic compounds. Today, one of the most important problems in the field of treatment is microbial resistance to antibiotics. Now, if a new compound has an antibacterial effect, it will be a great service to the world. The aim of this study was to investigate the biological effects (cytotoxic, antibacterial and antioxidant) of Cirsium lappaceum plant.Method:The aerial part of Cirsium lappaceum plant was prepared and after identification, it was dried in a dark environment away from light, then it was powdered by a mill. Then, ۵۰۰ grams of the powder was extracted by soaking with methanol-water solvent, the resulting extract was concentrated by rotary and after that by placing it on the oven. The resulting extract was used for biological experiments. The antibacterial effect was investigated by MIC and MBC methods and non-growth aura on S.aureus, S.epidermidis, K.rhizophila, B.subtilis, E.coli, P.aeruginosa, S.enterica, K.pneumoniae, S.typhimurium bacteria. The cytotoxic effect of the extract was investigated by colonization test method on A۲۷۸۰, MCF۷, A۵۴۹ and HT۲۹ cell lines. The antioxidant effect was also evaluated by determining total phenolic and flavonoid content and DPHH test.Results:DPPH free radical inhibition method was used to investigate the antioxidant effect of this plant. The value of IC-۵۰ for this plant was calculated as ۳۶.۷۸±۸.۸۳ mg/ml, and to calculate the amount of total phenolic and flavonoid content, Folin Sieve Calto and aluminum chloride methods were used. The total phenolic content of the plant was ۴.۳۵% compared to the standard of gallic acid, and flavonoid content was ۲۰.۶۵ μg/ml compared to the routine standard. Cytotoxicity test results show the effect with IC۵۰ in MCF۷ ۲۷۷.۱ ±۳۹.۲۳ μg/ml, in A۵۴۹ ۵۰۷±۷۲ μg/ml and in A۲۷۸۰ ۱۷۷± ۳۹ μg/ml cell lines.Conclusion:In examining the antioxidant activity of the plant, we found a direct relationship between total phenolic content and antioxidant effect. The methanol-blue extract of the examined plant has a selective effect on the ovarian cell line, also this plant has a better effect on gram-positive bacteria and among gram-positives it has the best effect on S. epidermidis. In the investigation of the antifungal effect, no effect was observed on the researched fungi.