Randomised controlled trial of homoeopathy versus placebo in perennial allergic rhinitis with overview of four trial series

Objective To test the hypothesis that homoeopathy is a placebo by examining its effect in patients with allergic rhinitis and so contest the evidence from three previous trials in this series. Design Randomised, double blind, placebo controlled, parallel group, multic entre study. Setting Four general practices and a hospital ear, nose, and throat outpati ent department. Participants 51 patients with perennial allergic rhinitis. Intervention Random assignment to an oral 30c homoeopathic preparation of p rincipal inhalant allergen or to placebo. Main outcome measures Changes from baseline in nasal inspiratory peak now a nd symptom visual analogue scale score over third and fourth weeks after ra ndomisation. Results Fifty patients completed the study. The homoeopathy group had a sig nificant objective improvement in nasal airflow compared with the placebo g roup (mean difference 19.8 1/min, 95% confidence interval 10.4 to 29.1, P = 0.0001). Both groups reported improvement in symptoms, with patients takin g homoeopathy reporting more improvement in all but one of the centres, whi ch had more patients with aggravations. On average no significant differenc e between the groups was seen on visual analogue scale scores. Initial aggr avations of rhinitis symptoms were more common with homoeopathy than placeb o (7 (30%) v 2 (7%), P = 0.04). Addition of these results to those of three previous trials (n = 253) showed a mean symptom reduction on visual analog ue scores of 28% (10.9 mm) for homoeopathy compared with 3% (1.1 mm) for pl acebo (95% confidence interval 4.2 to 15.4, P = 0.0007). Conclusion The objective results reinforce earlier evidence that homoeopath ic dilutions differ from placebo.