The objective of the present study was to investigate the effects of aqueous extract from the healthful decoction utilizing Phellinus linteus (HDPL) on the growth of human lung carcinoma A549 cells. HDPL treatment declined the cell viability of A549 cells in a concentration-dependent manner and the anti-proliferative effects by HDPL treatment were associated with morphological changes such as membrane shrinking and cell rounding up. HDPL treatment did not affect the distribution of the cell cycle. Western blot analysis and RT-PCT data revealed that the levels of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21WAF1/CIP1 in HDPL-treated A549 cells were remained unchanged. However, HDPL treatment inhibited the expression of cyclooxygenase-2 (COX-2) mRNA and protein in a concentration-dependent fashion. Additionally, the expression of human telomerase reverse transcriptase (hTERT), a main determinant of the telomerase enzymatic activity, was progressively down-regulated by HDPL treatment. Taken together, these findings suggest that HDPL-induced inhibition of human lung cancer cell proliferation is associated with the inhibition of several major growth regulatory gene products, such as COX-2 and hTERT, and HDPL may have therapeutic potential in human lung cancer.