MRL-lpr/lpr mice were treated with Tripterygium Wilfordii Hook-F (TWHF), a Chinese herbal medicine successfully used for human rheumatoid arthritis. Dramatic prolongation of survival and the reduction of urinary protein were observed in mice treated with a high dose of TWHF (20 mg/kg, three times a week) compared to the control animals receiving solvent alone. A slight but significant reduction was also seen in the degree of lymphadenopathy and arthritis with the high dose treatment. Surprisingly, no significant difference was present in IgM rheumatoid factor and IgG anti-double-stranded DNA antibody levels or in the histopathology of lupus nephritis. These results indicate the dissociation of histopathological renal disease and the degree of proteinuria or the life span. Although further pharmacological analysis is required, TWHF might be potentially useful for diseases such as systemic lupus erythematosus or nephrotic syndrome.