Ivy leaf (Hedera helix) for acute upper respiratory tract infections: an updated systematic review

PURPOSE: Acute cough due to viral upper respiratory tract infections (URTIs) and bronchitis is a common reason for patients to seek medical care. Non-antibiotic over-the-counter cough medications such as ivy leaf extract are frequently used but their efficacy is uncertain. Our purpose 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. METHODS: We searched MEDLINE, EMBASE, the Cochrane Library, and clinical trial registries from December 2009 to January 2020. Randomized controlled trials (RCTs), controlled clinical trials (CCTs), and observational studies (OSs) investigating ivy leaf mono- or combination preparations were included. Two independent reviewers assessed records for eligibility and risk of bias and performed data extraction. RESULTS: Six RCTs, 1 CCT, and 4 OSs were identified. Since the publication of our previous review, the number of RCTs has increased. All studies concluded that ivy leaf extract is an effective and safe option for the treatment of cough due to URTIs and bronchitis. Three RCTs reported a more rapid reduction in cough severity and/or frequency under ivy leaf treatment. 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. CONCLUSIONS: 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. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00228-021-03090-4.