Plant Extracts Ranked for Allergic Rhinitis Relief in Major Meta-Analysis

For hundreds of millions of people worldwide, allergic rhinitis is more than a seasonal nuisance. The sneezing, congestion, itching and watery eyes that define the condition erode sleep, concentration and quality of life, and conventional therapies—from antihistamines to nasal corticosteroids and allergen-specific immunotherapy—leave many patients inadequately controlled. Now, a systematic review and network meta-analysis published in BMC Complementary Medicine and Therapies offers one of the most comprehensive comparisons to date of plant-derived active substances as potential treatments, ranking 24 botanical interventions across symptom scores, inflammatory markers and quality-of-life measures.

The research team, led by Ruizhi Fan, Zeyuan Li, Meihua Liang, Chunyan Zhao, Xueli Wang and corresponding author Zhibin Zhang of Shanxi University of Traditional Chinese Medicine, systematically searched PubMed, Embase, the Cochrane Library and Web of Science for randomized controlled trials testing plant-based interventions in patients with allergic rhinitis. Their final dataset comprised 27 randomized controlled trials encompassing 1,681 participants, with studies published up to March 2025. Methodological quality was assessed with the Cochrane Risk of Bias Tool, and the statistical analysis, performed in Stata 15.4, employed a Bayesian network meta-analysis framework using Markov Chain Monte Carlo methods to allow both direct and indirect comparisons among interventions.

What distinguishes a network meta-analysis from a conventional pairwise meta-analysis is its ability to rank treatments even when they have never been compared head-to-head in a single trial. The team quantified each intervention’s performance using SUCRA values—the surface under the cumulative ranking curve—where a value approaching 100 percent signals the highest probability of being the most effective option in the network. The interventions ranged from well-known supplements such as spirulina and Pycnogenol to more specialized botanicals including Benifuuki green tea, broccoli sprout extract, fermented red ginseng, Perilla frutescens extract, Nigella sativa oil, stinging nettle root extract and Petasites hybridus leaf extract (Ze 339).

The rankings that emerged are strikingly specific to the outcome measured. For Total Nasal Symptom Scores, the primary clinical metric combining congestion, rhinorrhea, sneezing and itching, tomato extract rose to the top with a SUCRA value of 78.0 percent, suggesting it may offer the most consistent relief of core nasal symptoms. Glycyrrhiza glabra, commonly known as licorice, led the network for reducing Sino-Nasal Outcome Test-22 scores—a validated patient-reported instrument capturing nasal, sleep and emotional domains of sinonasal disease—with a SUCRA of 92.6 percent.

Spirulina, the blue-green cyanobacterium widely consumed as a nutritional supplement, achieved a perfect SUCRA of 100 percent for reducing Visual Analog Scale symptom ratings while simultaneously improving quality of life. Fermented red ginseng dominated the immunological endpoint, reducing serum immunoglobulin E levels with a SUCRA of 99.7 percent—a finding of mechanistic interest because IgE is the antibody class central to the allergic cascade, binding to mast cells and triggering histamine release upon allergen exposure. Flos Magnoliae volatile oil, derived from the flower buds used in traditional Chinese medicine for nasal obstruction, ranked highest at lowering serum eosinophil counts, with a SUCRA of 80.6 percent. Eosinophils are white blood cells recruited to inflamed nasal tissue in allergic disease, and their reduction signals a dampening of the underlying inflammatory process rather than merely masking symptoms.

Perhaps the most complete immunological result came from Phlai, a Thai ginger-family rhizome (Zingiber cassumunar), which achieved a perfect SUCRA of 100 percent for reducing interleukin-5 levels. IL-5 is the key cytokine driving eosinophil maturation, activation and survival, positioning Phlai upstream in the inflammatory hierarchy. Together, these biomarker findings sketch a plausible biological picture: several of the top-performing botanicals appear to act on the T helper 2-skewed immune signaling that underlies allergic rhinitis, modulating cytokines such as IL-4, IL-5 and IL-13, the NF-κB transcriptional pathway, and downstream effectors including eosinophils, leukotrienes and IgE.

The authors conclude that tomato extract, Glycyrrhiza glabra extract, spirulina, fermented red ginseng, Flos Magnoliae volatile oil and Phlai demonstrate more favorable efficacy profiles than the other plant-derived interventions in improving symptoms and quality of life. The study protocol was prospectively registered on PROSPERO (CRD420251052539), and the review’s breadth—spanning 24 substances and multiple laboratory indicators including interleukins, tumor necrosis factor-alpha, interferon-gamma and toll-like receptor signaling markers—makes it a valuable roadmap for prioritizing future trials.

Cautions remain, however. Network meta-analyses inherit the limitations of their component trials, which in this field often involve small samples, heterogeneous dosing, variable extract standardization and short follow-up periods. The certainty of evidence for individual comparisons can vary substantially, and indirect rankings should be read as hypothesis-generating rather than definitive prescriptions. The researchers note no competing interests, and the work was funded by the Department of Traditional Chinese Medicine Otorhinolaryngology of Shanxi University of Traditional Chinese Medicine and the Scientific Research Project of Shanxi Provincial Health Commission.

Even with those caveats, the analysis arrives at a moment of genuine clinical need. Allergic rhinitis prevalence continues to climb globally, and patients increasingly seek adjunctive or alternative options with favorable safety profiles. If larger, well-designed randomized trials confirm the rankings reported here—particularly for tomato extract on nasal symptoms and spirulina on patient-rated outcomes—everyday dietary and herbal compounds could earn a more rigorous, evidence-based place alongside conventional therapy. The study, published open access on 10 September 2026, invites both clinicians and researchers to look more closely at the pharmacological potential hiding in ordinary plants.

Subject of Research: Network meta-analysis of plant-derived active substances for the treatment of allergic rhinitis

Article Title: Active substances of plants in the treatment of allergic rhinitis: a systematic review and network meta-analysis

Article References: Fan, R., Li, Z., Liang, M., Wang, X., Zhao, C., & Zhang, Z. (2026). Active substances of plants in the treatment of allergic rhinitis: a systematic review and network meta-analysis. BMC Complementary Medicine and Therapies. https://doi.org/10.1186/s12906-026-05571-4

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05571-4

Keywords: allergic rhinitis, plant extracts, network meta-analysis, spirulina, tomato extract, fermented red ginseng, Glycyrrhiza glabra, Flos Magnoliae volatile oil, Phlai, immunoglobulin E, interleukin-5, randomized controlled trials