Objects We tried to establish a rat low back pain model using continuous infusion of nicotine, and examined the effect of a nonprotein extract isolated from inflamed skin of rabbits inoculated with vaccinia virus (Neurotropin) on gait abnormality and hyperalgesia of the model. Furthermore, we clarified the action mechanism of Neurotropin. Methods Rats were implanted s.c. with osmotic pumps filled with a nicotine solution Walking time and 50% withdrawal pain threshold were measured using a rotarod device and von Frey filaments, resp. The nicotine-treated rats were orally administered with Neurotropin, pregabalin, celecoxib, or limaprost daily from 2 to 7 wk after nicotine exposure to assess the effect of drugs on behavior activities. To clarify the action mechanism of Neurotropin for these behavior activities in nicotine-induced low back pain model rats, the influence of intrathecal receptor antagonist for noradrenaline (NA) α2, 5-hydroxytryptamine (5-HT)2A, or 5-HT3 was examined Results Walking time and 50% withdrawal pain threshold of nicotine-treated rats were decreased compared with sham rats. Limaprost and pregabalin ameliorated either walking time or 50% withdrawal pain threshold, but not both. Neurotropin improved both behavior parameters. NA α2, 5-HT2A, or 5-HT3 receptor antagonist reduced the effect of Neurotropin on 50% withdrawal pain threshold but not walking time. Conclusion Sustained exposure to nicotine induced gait disturbance in addition to hyperalgesia in rats. The drug clin. used for neuropathic pain such as pregabalin was effective for hyperalgesia and the drug improving blood flow was effective for gait disturbance in this model. It was considered that Neurotropin improved hyperalgesia and gait abnormality by activating the descending pain inhibitory system and its blood flow improving action in nicotine-exposed rats. These results may suggest the usefulness of Neurotropin on patients with low back pain.