Studies performed on Essential oil of Syzygium aromaticum (EOSa) from the Romanian market indicate a relative content of 73.18% in Eugenol. Due to this compound, the antioxidant activity determined with chemiluminescence technique, using luminol as a witness, give an average value of 98%. Studies performed on cell line THP-1, reveal that if this cell line is treated with EOSa, after 24 h of exposure at a concentration of minimum 0.05 mu L/mL EOSa, then 27% of tumor cells are found in the apoptosis stage. Increasing EOSa concentration in the culture media of THP-1 cells up to 10 mu L/mL does not affect the level of apoptotic cells. This value remains constant for the concentrations of EOSa situated in the range of (0.05 divided by 10)mu L/mL. The flowcitometry studies show that, if the concentration of EOSa increase up to 10 mu L/mL, then 16% of THP-1 are found in the stage of necrosis. The biological tests performed in vitro reveal a high antioxidant activity of Syzygium aromaticum oils and a possible antitumor effect induced by apoptosis, due to the high content of Eugenol from bioproduct.