Intermittent exposure to hyperbaric oxygen (HBO) can protect against oxygen toxicity, but little is known about its mechanisms.In this study, we examined the effects of intermittent HBO exposure on the levels of peroxiredoxin 6 (Prdx 6) in lung and brain tissues.Mice were exposed to 280 kPa O2 for 60 min, followed by 30-min exposure to 20% O2/N2 mixture with equal pressure, repeated six times.Then the Prdx 6 protein levels in lung and brain were determined.Compared with normal group, both intermittent and continuous HBO exposures increased Prdx 6 in lung and brain and that these increases were even more significant 24 h after cessation of exposure.There were no obvious differences in Prdx 6 levels for lung and brain from intermittent or continuous groups immediately upon cessation of exposure.However, 24 h after cessation of exposure, Prdx 6 levels in intermittent group were higher than those of continuous group for both lung and brain.Altogether, these data showed that intermittent HBO exposure can increase lung and brain Prdx 6 protein levels, and thereby improve the antioxidant capacity of these tissues.