In order to examine the mechanism of apoptosis-induction during 24-h incubation of lung cancer cells with D. calcarata extracts, RT-PCR was used to measure the expression of several apoptotic genes, including p53, Bcl-2 and Bax. In WE-treated H1437 cells, apoptosis was associated with increased mRNA expression of p53, whereas in A549 and H1573 cells, the mRNA expressions of Bcl-2 and p53 were decreased. The gene discussed is TP53; the disease is lung carcinoma.