• homeopathy;
  • randomized controlled trial;
  • ultramolecular

Aims  To investigate if ultramolecular homeopathy has any clinical effects. This was assessed using the proving of the homeopathic remedy Belladonna given at an ultramolecular dose (30C), as a model. A proving states that when a homeopathic remedy is given to a healthy person, they will experience symptomatic effects specific to that remedy. If ultramolecular doses are clinically active, the Belladonna 30C group should experience more true Belladonna proving symptoms than the placebo group.

Methods  Healthy subjects (n = 253), aged 18–30 years, took part in this double-blind, randomized placebo-controlled study. Total study duration was 4 weeks. Subjects were randomized before 1 week placebo run-in. They received 2 weeks of treatment intervention (Belladonna 30C or placebo) and were followed up for 1 week. Subjects recorded any symptoms experienced during the total study period on a daily basis using a structured questionnaire. Symptom diaries were analysed blind to determine if each subject had proved or not (based on predefined criteria). The main outcome was the proportion of subjects who had proved in each treatment group.

Results  No significant group differences in proving rates were observed [Belladonna provers N = 14 (13.9%); placebo provers N = 15 (14.3%); mean difference − 0.4%, 95% confidence interval − 9.3, 10.1] based on intention to treat analysis. Primary outcome was not affected by seasonality or the individual's attitude to complementary medicine.

Conclusion  Ultramolecular homeopathy had no observable clinical effects.