The present study aimed to delineate the actions of cigarette smoke extracts on esophageal squamous-cell carcinoma cell growth in vitro. Both chloroform- and ethanol-extracts from cigarette smoke stimulated human esophageal squamous carcinoma EC109 cell proliferation. Chloroform- and ethanol-extracts also upregulated beta-adrenoceptors expression in EC109 cells. Cyclo-oxygenase-2 (COX-2) expression was increased by chloroform-extract. The stimulatory actions of chloroform-extract on cell proliferation and COX-2 expression were abolished by beta(1)- and beta(2)-adrenoceptor selective antagonists, implicating that COX-2 was downstream to the beta-adrenoceptors. Collectively, the promoting action of chloroform-extract from cigarette smoke on esophageal squamous-cell carcinoma cell proliferation is beta-adrenoceptor- and COX-2-dependent.