Abstract： Objective To investigate the optimal concentration and site for ozoneadministration to relieve neuropathic pain in rats. Methods Twenty-four adult male rats with sciaticnerve injury (SNI) were randomized equally into 4 groups, and received ozone injections for analgesia atdifferent sites, namely the operative site, the sciatic nerve, the L5 spinal nerve or the operative site inaddition to the L5 spinal nerve. Another 4 groups of rats with SNI (n=6) had ozone injections at theconcentrations of 40, 50, 60, or 70 μg/mL, all administered at both the operative site and the L5 spinalnerve. The analgesic effects of the ozone injections were evaluated using paw withdrawal threshold test inall the rats. Results In rats with ozone injection at both the operative field and the L5 spinal nerve, themechanical pain threshold was significantly increased in comparison with that in rats with injections atother sites (P<0.05), but different doses of ozone simultaneously injected at the two sites did not producesignificant differences in the pain threshold (P>0.05). Conclusion Ozone produces obvious analgesiceffects in rats with SNI-induced neuropathic pain when injected at both the operative site and thespinal nerve, and ozone within the concentration range from 40 to 70 μg/mL has similar analgesic effect.