Elderberry for prevention and treatment of viral respiratory illnesses: a systematic review

Prevention: randomized, double‑blind, placebo‑controlled trial; 312 adults (mean age 51, SD 16); 34% men; generally healthy travelers. Treatment: randomized controlled trials with outpatients: Kong 2009 (N=64; age 20–59), Zakay-Rones 1995 (N=27; age 5–56), Zakay-Rones 2004 (N=60; mean age ~30), Rauš 2015 (N=420; mean age 37.2; 50% men). Ex vivo cytokine studies included: Curtis 2009 (RCT with 52 healthy postmenopausal women, 12 weeks), Kirichenko 2016 (comparative before–after in healthy volunteers), Ivanova 2015 (before–after in 22 healthy volunteers).

Prevention (Tiralongo 2016): capsule with 300 mg proprietary elderberry extract, taken 2–3 times daily for 15–16 days. Treatment regimens: Kong 2009: lozenge with 175 mg elderberry extract, taken four times daily for 2 days. Zakay-Rones 1995: Sambucol elderberry syrup (38% elderberry extract) taken as 1 tablespoon (adults) or 2 times daily (children) for 3 days. Zakay-Rones 2004: Sambucol elderberry syrup taken four times daily for 5 days. Rauš 2015: Echinaforce Hotdrink (elderberry + echinacea), 5 mL, taken 3–5 times daily for 10 days (comparison included oseltamivir/placebo).

Prevention: Elderberry did not significantly reduce the risk of developing a common cold (12/154 vs 17/158; RR 0.69, 95% CI 0.34–1.39; p=0.30). Among those who contracted a cold, duration was about 2 days shorter with elderberry (roughly MD −2.13 days; 95% CI −4.16 to −0.10; p=0.04) and severity was lower (Jackson score; MD −13.69; 95% CI −24.54 to −2.84; p=0.01). Certainty of these prevention findings is very low due to risk of bias and imprecision. Treatment: for influenza, three small RCTs (n=87 total) suggested possible reduced duration and faster recovery with elderberry vs placebo, but small samples and methodological concerns yield very low certainty. A larger trial comparing a mixed elderberry–echinacea product (Echinaforce Hotdrink) to oseltamivir suggested possible fewer complications/adverse events with the herbal product and similar recovery by days 5, but certainty is low. Ex vivo evidence shows elderberry can modulate inflammatory markers (e.g., reductions in IL‑1, TNF‑α, CRP in some studies), but findings are inconsistent and do not translate to clear clinical outcomes. Overall, elderberry may be safe and possibly help shorten illness in influenza/colds, but benefits and harms are uncertain; more high‑quality trials are needed.

Small number of trials with limited sample sizes; variable risk of bias and incomplete outcome reporting; heterogeneity in elderberry products and co‑interventions (e.g., echinacea, oseltamivir) limit pooled interpretation; adverse event reporting often lacking or inconsistent; ex vivo findings may not reflect clinical effects.