The influence of moxibustion, a traditional Chinese medical treatment, on type II collagen-induced arthritis (CIA) was examined in DBA/1J mice in vivo. Mice were immunized intradermally twice at the 3-week interval with bovine type II collagen (C Il). The main incidence of arthritis started about on day 30 and lasted to day 60 after the first immunization. Moxibustion with three different regimens, was applied at the acupoint equivalent to GV 4 every other day. Moxibustion, from day 0 to day 30 after the first immunization, suppressed the onset and development of arthritis, as well as anti-collagen antibody level. Treatment with moxibustion, from the day 31 to day 60, also resulted in a significant inhibition of progression of arthritis and production of anti-C II antibody. Thirdly we examined the influence of moxibustion on the established arthritis. Moxibustion given from day 61 to day 120, significantly but mildly decreased the anti-C II antibody level in diseased mice, while the bone erosion and joint destruction were not affected. These results indicate that moxibustion could prevent the incidence and attenuates the development of murine CIA.