The effects of Sambucus nigra berry on acute respiratory viral infections: A rapid review of clinical studies

BRIEF OVERVIEW: Collectively the evidence obtained from across five clinical studies involving 936 adults indicate that mono-herbal preparations of Sambucus nigra L. berry (S.nigra), when taken within 48 hours of the onset of acute respiratory viral infection, may reduce the duration and severity of common cold and influenza symptoms in adults. There is currently no evidence to support the use of S.nigra berry for the treatment or prevention of COVID-19. Given the body of evidence from preclinical studies demonstrating the antiviral effects of S.nigra berry, alongside the results from clinical studies involving influenza viral infections included in this review, pre-clinical research exploring the potential effects of S.nigra berry on COVID-19 are encouraged. VERDICT: The evidence included in this review is mostly derived from clinical studies involving adult participants and examining short-term use of commercial formulations of S.nigra berry for up to 16 days. Findings from included studies suggest that mono-herbal preparations of S.nigra berry (in extract or lozenge formulation) may reduce influenza-type symptoms, including fever, headache, nasal congestion and nasal mucous discharge in adults, when taken within the first 48 hours of symptom onset. Within 2–4 days of S.nigra treatment, most adult participants experienced significant symptom reduction, by an average of 50%. Evidence regarding the effectiveness of S.nigra berry on the symptom of cough, and need for/use of medicines (including antibiotics) to treat acute respiratory infections, is currently unclear and inconsistent. Adverse events were rare with no serious events reported. Adverse events, reported in two studies, were more common in comparators than in treatments. There is currently no reliable or sufficient scientific evidence to support the use of S.nigra in pregnant or lactating women.