title: Rhodiola crenulata extract for prevention of acute mountain sickness: a randomized, double-blind, placebo-controlled, crossover trial.
abstract: BACKGROUND
  Rhodiola crenulata (R. crenulata) is widely used to prevent acute mountain sickness in the Himalayan areas and in Tibet, but no scientific studies have previously examined its effectiveness. We conducted a randomized, double-blind, placebo-controlled crossover study to investigate its efficacy in acute mountain sickness prevention.
  
  
  METHODS
  Healthy adult volunteers were randomized to 2 treatment sequences, receiving either 800 mg R. crenulata extract or placebo daily for 7 days before ascent and 2 days during mountaineering, before crossing over to the alternate treatment after a 3-month wash-out period. Participants ascended rapidly from 250 m to 3421 m on two separate occasions: December 2010 and April 2011. The primary outcome measure was the incidence of acute mountain sickness, as defined by a Lake Louise score ≥ 3, with headache and at least one of the symptoms of nausea or vomiting, fatigue, dizziness, or difficulty sleeping.
  
  
  RESULTS
  One hundred and two participants completed the trial. There were no demographic differences between individuals taking Rhodiola-placebo and those taking placebo-Rhodiola. No significant differences in the incidence of acute mountain sickness were found between R. crenulata extract and placebo groups (all 60.8%; adjusted odds ratio (AOR) = 1.02, 95% confidence interval (CI) = 0.69-1.52). The incidence of severe acute mountain sickness in Rhodiola extract vs. placebo groups was 35.3% vs. 29.4% (AOR = 1.42, 95% CI = 0.90-2.25).
  
  
  CONCLUSIONS
  R. crenulata extract was not effective in reducing the incidence or severity of acute mountain sickness as compared to placebo.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT01536288.
authors.forename: Te-Fa
authors.initials: TF
authors.lastname: Chiu
authors.forename: Lisa Li-Chuan
authors.initials: LL
authors.lastname: Chen
authors.forename: Deng-Huang
authors.initials: DH
authors.lastname: Su
authors.forename: Hsiang-Yun
authors.initials: HY
authors.lastname: Lo
authors.forename: Chung-Hsien
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of Emergency Medicine, Taipei Medical University Hospital, Wu-Hsing Street, Taipei, Taiwan. mountainwangsh@gmail.com.
authors.forename: Shih-Hao
authors.initials: SH
authors.lastname: Wang
authors.forename: Wei-Lung
authors.initials: WL
authors.lastname: Chen
mesh_terms: D000208:Acute Disease / Q000628:therapy; D000328:Adult; D000532:Altitude Sickness / Q000188:drug therapy / Q000517:prevention & control*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000008:administration & dosage*; D029771:Rhodiola / Q000737:chemistry*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010936:Plant Extracts