AIMTo study the systemic anti-inflammatory actions of interleukin-1 (IL-1) blockers, OB-101 and OB-186.METHODSPrevention of palm swelling induced by carrageenin injection was used as an animal model of systemic anti-inflammation efficacy.RESULTSBoth OB-101 and OB-186 (10-30 mg.kg-1) were approximately 10-30-fold more potent than aspirin (300 mg.kg-1) to inhibit carrageenin-induced systemic inflammation. The LD50 of OB-101 and OB-186 were at least 20 g.kg-1 i.g., indicating that they were extremely safe agents with a therapeutic index (LD50/ED50) of at least 2000.CONCLUSIONThese IL-1 blockers are extremely safe systemically and are useable for the treatment of systemic inflammation such as rheumatoid arthritis.