We studied the effects of a spicamycin derivative, KRN5500, on two animal models of neuropathic pain (Chung and Bennett models) and a nociceptive pain model by using Complete Freund's adjuvant. After the establishment of mechanical allodynia by using the previously mentioned models, a single intraperitoneal injection of KRN5500 produced significant attenuation of mechanical allodynia in both neuropathic pain models. However, this effect was not observed in rats that had a nociceptive injury (Complete Freund's adjuvant). Furthermore, this experimental drug did not alter the mechanical pain threshold (by using von Frey filament test) on normal, uninjured rats. We have demonstrated that KRN5500 may have value in the treatment of neuropathic pain.