Background: Neuropathic pain is a chronic pain that affects on the patient’s quality of life. Use of herbal instead of synthetic drugs recently has been increased due to side effects of synthetic drugs and herbal effective components. Flavonoids are herbal compounds that have analgesic and anti-inflammatory effects. Because Allium cepa L. has a great amount of flavonoids, this study has been designed to evaluate analgesic effects of alcoholic extract of Allium cepa L. on neuropathic pain behavior in chronic constriction injury model in rats.

Materials and Methods: In this experimental study, neuropathic pain induced by chronic constriction injury (CCI model) in Rats. Animals were randomly divided into 4 groups (n=10 for each): Sham, CCI model, receiving red onion hydroalcoholic extract at a dose of 100 mg/kg and a group receiving gabapentin (100 mg/kg). Red onion extract and gabapentin were administered by gavage for 21 days. Using thermal hyperalgesia, mechanical and thermal allodynia tests, the analgesic effects of extract have been measured.

Results: Findings of this study revealed that CCI surgery on rats induced hyperalgesia, mechanical and thermal allodynia. Daily intakes of alcoholic extract of red onion and gabapentin significantly increase the paw withdrawal latency; increase the threshold to mechanical allodynia and decrease in response to acetone.

Conclusion: Oral use of alcoholic extract of Allium cepa L. reduces neuropathic pain behavior in CCI model in rats.