Tripterine is one of the active components isolated from Tripterygium wilfordii Hook.f. In this study tripterine was shown to inhibit the antibody response of mouse splenocytes to SRBC both in vitro and in vivo either by primary or secondary stimulation. Tripterine was also found to significantly inhibit cotton pellet induced granuloma growth in rats and depress the delayed hypersensitive reaction of mouse skin to dinitrochlorobenzene (DNCB). Besides, it also increased the sleeping time of mouse induced by pentobarbital sodium. From the results stated above, it appears that tripterine might be useful in the treatment of inflammatory diseases or autoimmune diseases.