While more and more studies are being conducted on the enigmatic topic of homeopathy, it's important to consider each particular study before drawing any conclusive results — for not all studies are created equal.
Researchers from the Department of Epidemiology and Health Care Research at the University of Limburg in The Netherlands assessed the methodological quality of 107 controlled trials in 96 published reports between the 1970s and early '90s on the efficacy of homeopathy in humans. Two studies included in this comprehensive overview were rated very highly: Ferley, et al. (1987) and Reilly, et al. (1986). In the Ferley study, 247 patients received the polypharmaceutical homeopathic medicine Anas barbariae hepatis, cordis extractum C200, manufactured by Boiron in Newton Square, Penn., and sold as Oscilloccinum, for the treatment of influenza; 241 patients received a placebo. The recovery rate for homeopathic patients was 17 percent in 48 hours; the placebo group's recovery rate was 10 percent in 48 hours.
Similarly, the study by Reilly, et al., gave Pollen C30, prepared by a homeopathic pharmacist, to 74 patients who were suffering from pollen allergy; 70 patients were given a placebo. A change in 100 mm visual analog scale for the symptoms was 17 mm for the group treated with homeopathic medicine and 2.6 mm for the placebo group.
The small number of controlled trials undertaken to date makes it difficult to understand homeopathic medicine. This is especially true because homeopathy's mechanism of action is unknown or cannot be accounted for within our current level of understanding of pharmacology and physics.