Systematic review of the efficacy of ivy leaf (Hedera helix) in acute upper respiratory tract infections: an update.

Introduction: A common reason for patients to seek ambulatory medical care is acute cough due to viral upper respiratory tract infections (URTIs) or bronchitis. Non-antibiotic over-the-counter cough medications such as ivy leaf extract are frequently used or recommended, but their efficacy is uncertain. Our goal was to update our previous systematic review and evaluate the effectiveness and tolerability of ivy leaf in the treatment of acute URTIs in adult and pediatric populations. Method: MEDLINE, EMBASE, the Cochrane Library, and clinical trial registries from the dates December 2009 to January 2020 were searched. We included randomized controlled trials (RCTs), controlled clinical trials (CCTs) and observational studies (OSs) investigating ivy leaf mono- or combination preparations. Two independent reviewers assessed retrieved records for eligibility and risk of bias and performed data extraction. Results: Six RCTs, 1 CCT, and 4 OSs were identified. The number of RCTs has increased since the publication of our previous review. All studies concluded that ivy leaf extract is effective and safe. Three RCTs reported a more rapid reduction in cough severity and/or frequency under ivy leaf treatment as opposed to standard care or placebo; 5 studies utilized the Bronchitis Severity Scale (BSS, Figure 1). The clinical significance of these effects appears to be minimal. No serious adverse effects were reported. The overall quality of reporting was low and the risk of bias was high. Discussion: Ivy leaf preparations are safe for use in cough due to acute URTIs and bronchitis. However, effects are minimal at best and of uncertain clinical importance.