title: The placebo effect and homeopathy.
abstract: BACKGROUND
  Like other forms of medicine, including Complementary and Alternative Medicine (CAM), homeopathy elicits expectations in patients. The physician-patient relationship, personal and comprehensive treatment and lack of adverse effects are elements in creating positive expectations. Other elements may be associated with negative expectations.
  
  
  METHODS
  We conducted a systematic literature review on placebo and nocebo effects in acupuncture and homeopathy using Medline.
  
  
  RESULTS
  Findings on the psychophysiological and neuromediating mechanisms of the placebo-nocebo phenomenon are reviewed. Studies of these effects reveal how expectations and unconscious conditioning can be measured by imaging and EEG methods. They result in significant, non-specific therapeutic effects, which may confuse the evaluation of the specific therapeutic effects treatment, hampering selection of the simillimum.
  
  
  CONCLUSIONS
  Directions for future research on non-specific therapeutic effects of homeopathy to improve clinical practice and clinical research are discussed.
authors.affiliation: Department of Internal Medicine, School of Medicine, Universidade de Sao Paulo, Sao Paulo, Brazil.
authors.forename: Marcus Z
authors.initials: MZ
authors.lastname: Teixeira
authors.forename: Cristina H F F
authors.initials: CH
authors.lastname: Guedes
authors.forename: Patrícia V
authors.initials: PV
authors.lastname: Barreto
authors.forename: Mílton A
authors.initials: MA
authors.lastname: Martins
mesh_terms: D015670:Acupuncture Therapy; D001921:Brain / Q000503:physiopathology; D002986:Clinical Trials as Topic; D003865:Major Depressive Disorder / Q000188:drug therapy; D006705:Homeopathy; D006801:Humans; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology; D010300:Parkinson Disease / Q000188:drug therapy; D015990:Placebo Effect