We assessed whether radon inhalation inhibited carrageenan-induced inflammation in mice.Carrageenan (1% v/v) was injected subcutaneously into paws of mice that had or had not inhaled approximately 2000 Bq/m 3 of radon for 24 hr. Radon inhalation significantly increased superoxide dismutase (SOD) and catalase activity and significantly decreased lipid peroxide levels in mouse paws, indicating that radon inhalation activate antioxidative functions. Carrageenan administration induced paw edema and significantly increased tumor necrosis factor-alpha (TNF-α) and nitric oxide in serum. However, radon inhalation significantly reduced carrageenan-induced paw edema. Serum TNF-α levels were lower the radon-treated mice than in sham-treated mice. In addition, SOD and catalase activity in paws were significantly higher in the radon-treated mice than the sham-treated mice. These findings indicated that radon inhalation had anti-inflammatory effects and inhibited carrageenan-induced inflammatory paw edema.