British researchers investigated whether or not ultramolecular homoeopathy has any clinical effects. This was assessed using the proving of the homoeopathic remedy Belladonna given at an ultramolecular dose (30C) as a model. Healthy subjects (n = 253), aged 18–30 years, took part in this double-blind, randomised, placebo-controlled study. Total study duration was 4 weeks. Subjects were randomised before a 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. No significant group differences in proving rates were observed [Belladonna provers n = 14 (13.9%); placebo provers n = 15 (14.3%); based on ITT analysis].