A Cochrane review ¹ included 6 studies with a total of 537 subjects. Five trials used acupuncture while one used acupuncture combined with drugs. Four trials compared acupuncture with drugs, while two compared acupuncture with manipulation and physical therapy respectively. No trials reported on the outcomes specified for this review, i.e. the efficacy of acupuncture in hastening recovery and reducing long-term morbidity from Bell's palsy. Harmful side effects were not reported in any of the trials. Flaws in study design or reporting (particularly uncertain allocation concealment and substantial loss to follow-up) and clinical differences between trials prevented conclusions about the efficacy of acupuncture.

Comment: The quality of evidence is downgraded by study quality (inadequate or unclear allocation concealment), by imprecise results (few patients and wide confidence intervals) and by inconsistency (heterogeneity in interventions and outcomes).