title: Veterinary homeopathy: systematic review of medical conditions studied by randomised trials controlled by other than placebo.
abstract: BACKGROUND
  No systematic review has previously been carried out on randomised controlled trials (RCTs) of veterinary homeopathy in which the control group was an intervention other than placebo (OTP). For eligible peer-reviewed RCTs, the objectives of this study were to assess the risk of bias (RoB) and to quantify the effect size of homeopathic intervention compared with an active comparator or with no treatment.
  
  
  METHODS
  Our systematic review approach complied fully with the PRISMA 2009 Checklist. Cochrane methods were applied to assess RoB and to derive effect size using standard meta-analysis methods. Based on a thorough and systematic literature search, the following key attributes of the published research were distinguished: individualised homeopathy (n = 1 RCT)/non-individualised homeopathy (n = 19); treatment (n = 14)/prophylaxis (n = 6); active controls (n = 18)/untreated controls (n = 2). The trials were highly diverse, representing 12 different medical conditions in 6 different species.
  
  
  RESULTS
  No trial had sufficiently low RoB to be judged as reliable evidence: 16 of the 20 RCTs had high RoB; the remaining four had uncertain RoB in several domains of assessment. For three trials with uncertain RoB and without overt vested interest, it was inconclusive whether homeopathy combined with conventional intervention was more or was less effective than conventional intervention alone for modulation of immune response in calves, or in the prophylaxis of cattle tick or of diarrhoea in piglets.
  
  
  CONCLUSIONS
  Due to the poor reliability of their data, OTP-controlled trials do not currently provide useful insight into the effectiveness of homeopathy in animals.
authors.affiliation: British Homeopathic Association, Hahnemann House, 29 Park Street West, Luton, LU1 3BE, UK. rmathie@britishhomeopathic.org.
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mathie
authors.affiliation: Karl und Veronica Carstens-Stiftung, Am Deimelsberg 36, D-45276, Essen, Germany. j.clausen@carstens-stiftung.de.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Clausen
mesh_terms: D000818:Animals; D006705:Homeopathy / Q000379:methods / Q000662:veterinary*; D016032:Randomized Controlled Trials as Topic / Q000379:methods / Q000662:veterinary*; D012106:Research / Q000592:standards*; D014730:Veterinary Medicine / Q000379:methods*