title: Quality markers of drug information on the Internet: an evaluation of sites about St. John's wort.
abstract: OBJECTIVE
  We aimed to evaluate websites about St. John's wort for the quality of their content, including accuracy as reflected by statement of correct indication and mentioning of interacting drugs, the presence of formal criteria as reflected by adherence to published standards for health information on the Internet, and the validity of individual formal criteria as markers of content quality.
  
  
  METHODS
  The Internet was searched with the metasearch engine WebFerret for sites about St. John's wort. A cross-sectional survey of a representative sample of randomly selected sites (n = 208) was performed. The main outcomes were the percentage of sites fulfilling the two criteria of content quality, the percentage of sites exhibiting eight formal criteria, and the associations between formal criteria and criteria of content quality, as determined by multivariate logistic regression analysis.
  
  
  RESULTS
  Twenty-two percent (n = 45) of the websites correctly listed depression as the only indication for use of St. John's wort, and 22% (n = 46) identified at least one drug interaction with St. John's wort. Citing scientific publications was associated with mentioning the correct indication (odds ratio [OR] = 4.4; 95% confidence interval [CI]: 1.4 to 14) and mentioning of any interacting drug (OR = 6.0; 95% CI: 2.0 to 18). Absence of financial interest was associated with mentioning the correct indication (OR = 5.4; 95% CI: 2.2 to 14) and interacting drugs (OR = 3.1; 95% CI: 1.2 to 7.7).
  
  
  CONCLUSIONS
  The content quality of sites about St. John's wort was generally poor. Our results suggest that Internet users should prefer noncommercial sites that reference the information to scientific publications when searching for drug information.
authors.affiliation: Internal Medicine VI, Clinical Pharmacology and Pharmacoepidemiology, Ruprecht-Karls-University, Heidelberg, Germany.
authors.forename: Meret
authors.initials: M
authors.lastname: Martin-Facklam
authors.forename: Michael
authors.initials: M
authors.lastname: Kostrzewa
authors.forename: Falk
authors.initials: F
authors.lastname: Schubert
authors.forename: Christiane
authors.initials: C
authors.lastname: Gasse
authors.forename: Walter E
authors.initials: WE
authors.lastname: Haefeli
mesh_terms: D003430:Cross-Sectional Studies; D004346:Drug Information Services / Q000592:standards; D004347:Drug Interactions; D006801:Humans; D020902:Hypericum; D020407:Internet; D016015:Logistic Models