Herbal Inhalation Therapy for Allergic Rhinitis: A Systematic Review and Meta-Analysis

Background: Allergic rhinitis (AR) is a common immunological disorder characterized by nasal symptoms and impaired quality of life. Despite advances in pharmacotherapy, symptom control often remains inadequate. Herbal medicine atomized inhalation (HMAI), a modern adaptation of traditional East Asian fumigation, may offer an effective adjunct or alternative therapy. This systematic review and meta-analysis evaluated the clinical efficacy and safety of HMAI, emphasizing its role as a localized drug delivery system. Methods: Six databases were searched through 28 April 2025, for randomized controlled trials (RCTs) assessing HMAI for AR. Outcomes were pooled with random-effects meta-analysis; risk of bias and certainty of evidence were evaluated using Cochrane Risk of Bias 2.0 and GRADE. Results: Fourteen RCTs (n = 1606) met the inclusion criteria. HMAI significantly improved total effective rate compared with Western medicine (risk ratio = 1.20, 95% CI 1.09-1.32) and enhanced symptom relief when combined with Western or herbal treatments. However, the overall certainty of evidence ranged from moderate to very low due to methodological limitations across trials. Conclusions: HMAI may offer symptomatic benefits for patients with AR, particularly when used as an adjunct to existing therapies. Given the substantial variability and high risk of bias among included studies, these findings should be interpreted cautiously. Rigorous, placebo-controlled trials with standardized protocols are required to clarify the therapeutic role of HMAI in AR management.