An extract from a chili pepper plant is showing promise in the treatment of cluster headache and migraine disease.

The extract—capsaicin, from the plant capsicum annuum—has been used as a pain reliever for centuries, and a study showing its success as a treatment for headache and migraine pain was presented at the American Academy of Neurology (AAN) Annual Meeting in Philadelphia in late April and early May.

Maria Alexianu, MD, Ph.D., and Anjan Chatterjee, MD, MPH, reported on their study of 18 adult patients with a wide range of headache diagnoses who used intranasal capsaicin to treat the pain. Both physicians are neurologists. Dr.Chatterjee experiences migraine and is the founder of VR1 Inc., which is currently marketing Ausinil, an over-the-counter homeopathic nasal spray containing the chili pepper extract.

In the small trial, 13 patients experienced complete pain relief. Most of the remaining patients also reported some pain relief, and one patient reported no pain relief.

The relief came soon after use for most patients and lasted from 30 minutes to several hours. All of the patients experienced tearing of the eyes and a nasal sting lasting up to 10 minutes, but the 17 patients who reported pain relief continued to use the product and said the stinging sensation would not deter them from using the agent.

The researchers say they believe capsaicin works by desensitizing the trigeminal nerve and depleting CGRP, the neurotransmitter responsible for migraine pain.

“By depleting CGRP, intranasal capsaicin is able to specifically target the source of the headache pain. These results emphasize the potential that intranasal capsaicin may offer in terms of rapid pain relief to severe headache and migraine sufferers who are in need of new treatment options,” said Dr. Chatterjee.

More information about the product is available online. Because the study has not yet been published in a peer-reviewed journal, The National Headache Foundation’s President Arthur Elkind, MD, cautioned that the results should be considered preliminary, and he noted that the U.S. Food and Drug Administration has not approved the nasal spray.