Our Cochrane review on Capsaicin for non-allergic rhinitis has been published! Follow the link above to read the abstract and plain language summary. Here is an excerpt from our conclusion:

Capsaicin may be an option in the treatment of idiopathic non-allergic rhinitis. It is given in the form of brief treatments, usually during the same day. It appears to have beneficial effects on overall nasal symptoms up to 36 weeks after treatment, based on a few, small studies (low-quality evidence). Well-conducted randomised controlled trials are required to further advance our understanding of the effectiveness of capsaicin in non-allergic rhinitis, especially in patients with non-allergic rhinitis of different types and severity, and using different methods of capsaicin application.