AIM To investigate the anti-inflammatory properties of IL-6 on the development of IDDM(insulin dependent diabetes mellitus) in NOD mouse. METHODS IL-6 was administered exogenously in female NOD mice (spontaneous model) and cyclophosphamide-treated NOD mice (accelerated model) respectively. During the study period, the mice were evaluated for development of diabetes once a week. At the end of experiment, 8 euglycosuria mice from each group were sacrificed for histoimmunological analysis, and the production of TNF-? and IFN-? from spleen lymphoid cells were detected. RESULTS The incidence of IDDM in spontaneous model(33%) were significantly reduced after 12 weeks of treatment. TNF-?(P