Salicylate increased manganese-superoxide dismutase (Mn-SOD) gene expression, but decreased catalase (CAT) gene expression in the cochlea and various brain regions of mice with tinnitus. Spirulinaplatensis water extract reduced salicylate-induced overexpression of the Mn-SOD gene, but increased salicylate-induced downregulation of the CAT gene. With the exception of significantly increased SOD activity in the brainstem and inferior colliculus of the Spirulina group, SOD and CAT enzyme activities did not differ among the three groups. The tinnitus group had higher malondialdehyde (MDA) levels than the control group in the temporal and the frontal lobes. S.platensis water extract reduced salicylate-induced elevations of MDA levels in many brain areas. We proposed that altered expression of antioxidant genes may reflect states of oxidative stress associated with tinnitus.