Efficacy of Supportive Therapy of Allergic Rhinitis by Stinging Nettle (Urtica dioica) root extract: a randomized, double-blind, placebo-controlled clinical trial

In this study, we aimed at studying the benefit of Urtica dioica root extract in the management of allergic rhinitis. In a randomized double blind clinical trial, 74 patients with the signs and symptoms of allergic rhinitis and a positive skin prick test were randomly divided into 2 groups. The study group was treated with routine allergic rhinitis treatment and Nettle root extract (Urtidin®, Barij Essence Pharmaceutical), while the control group received placebo along with routine treatment for one month. Patients’ symptoms, eosinophil percentage on nasal smear, serum IgE, and IL-4, IL-5, interferon- γ levels were recorded. Clinical and laboratory findings were monitored and statistically analyzedBased on the Sino- Nasal Outcome Test 22, a significant improvement in clinical symptom severity was observed in both groups (P < .001). Nettle root extract lead to a marked reduction in mean nasal smear eosinophil count (P < .01). However, the mean IgE and IL4 and IL5 levels before and after treatment with Nettle root extract saw no significant changes (P > .1). Intergroup Pre- and Posttreatment laboratory findings suggested that there was a significant difference in posttreatment changes of mean IFN γ levels between the study and placebo group (P = 0.017) To summarize, the current study showed certain positive effects of Urtica dioica root extract in the management of allergic rhinitis but similar effects were demonstrated by placebo as well. We believe that our limitations underscore the need for larger, longer term studies of Nettle in the treatment of allergic rhinitis.