Tiger Milk Mushroom (Lignosus rhinocerus TM02) in Allergic Rhinitis: A Critical Reappraisal of the First Randomised Controlled Trial and the Human Evidence Base

The first randomised controlled trial of tiger milk mushroom (Lignosus rhinocerus TM02) in allergic rhinitis reported significant symptom relief associated with interleukin-5 downregulation. This review places that trial within the human evidence for the mushroom and reappraises its findings. Of 108 randomised patients, 52 (48%) were excluded from the main analysis, more from the TM02 arm (54%) than the placebo arm (43%). Unadjusted comparisons with placebo were not significant. Recalculated between-arm differences were 0.64 and 0.68 points on 15-point nasal symptom scores, with 95% confidence intervals of −1.15 to 2.43 and −1.03 to 2.39. Significant effects appeared only after adjustment for baseline immunoglobulin E in a full-interaction model; the reported standardised coefficients correspond to effects of 10 to 12 points, larger than the patients' baseline scores, consistent with a treatment coefficient evaluated at an immunoglobulin E level of 1 IU/mL. Interleukin-5 did not change in either arm. The trial was registered after the manuscript was submitted. The data support short-term tolerability but not efficacy. A prospectively registered, adequately powered trial with intention-to-treat analysis and prespecified, centred covariate adjustment is required before TM02 is recommended for allergic rhinitis.