[ABSTRACT] Objective: To observe the effect of andrographolide on the expression of tumor necrosis factor -alpha and interleukin-12 in activated macrophages. Methods: Mouse peritoneal macrophages were harvested from mice that had been injected i.p. earlier with thioglycollate,were then cultured in media with andrographolide, lipopolysaccharide was then added to the media.Tumor necrosis factor -alpha , interleukin-12a and interleukin-12b mRNA of the macrophages were detected by RT-PCR. Tumor necrosis factor alpha and interleukin-12 protein in the supernatants were detected by ELISA. Results：Andrographolide inhibit tumor necrosis factor -alpha , interleukin-12a and interleukin-12b mRNA as detected by RT-PCR in activated macrophages. Andrographolide inhibit both tumor necrosis factor alpha and interleukin-12 protein in a concentration-dependent manner as detected by ELISA. 1ug/ml andrographolide partially suppressed the production of tumor necrosis factor alpha, and 1ug/ml andrographolide significantly inhibited tumor necrosis factor alpha production. 1ug/ml andrographolide significantly inhibited nterleukin-12 production.. Conclusion: Andrographolide can inhibit the expression of both tumor necrosis factor and interleukin-12.