Here we show that Daidzein synergizes with Gefitinib via ROS mediated c-Jun nuclear translocation and suppresses EGFR-STAT/AKT/ERK signalling axis to induce a G0/G1cell cycle arrest and apoptosis in A549 and H1975 lung adenocarcinoma cells. The gene discussed is JUN; the disease is lung adenocarcinoma.