Patients may ask about taking elderberry for prevention and treatment of influenza. Products containing elderberry are promoted for relief of cold and flu symptoms and as an immune system booster.
AVAILABILITY — Elderberry is available commercially in tablets, capsules, syrups, and gummies (Sambucol, Zarbees Naturals, and others). Fresh or freeze-dried elderberries can be cooked and made into a solution or syrup. All elderberry products available in the US (most contain black elderberry) are considered herbal supplements; they are not FDA-approved for any indication. As with all herbal supplements, the potency and purity of elderberry products is unknown.
EFFICACY — No large randomized, controlled trials evaluating the effectiveness of elderberry for prevention or treatment of influenza have been conducted to date. Elderberry appears to have some activity against influenza virus strains in vitro.1-3 In two small studies (conducted outside the US), adults with influenza A or B virus infection taking elderberry extract reported a shorter duration of symptoms compared to those taking placebo.1,4
ADVERSE EFFECTS — Consuming uncooked blue or black elderberries can cause nausea and vomiting. The rest of the plant (bark, stems, leaves, and root) contains sambunigrin, which can release cyanide.
PREGNANCY AND LACTATION — No data are available on the safety of elderberry use during pregnancy or while breastfeeding.5
CONCLUSION — Prompt treatment with an antiviral drug such as oseltamivir (Tamiflu, and generics) has been shown to be effective in large randomized, controlled trials in reducing the duration of influenza symptoms, and it may reduce the risk of influenza-related complications.6 There is no acceptable evidence to date that elderberry is effective for prevention or treatment of influenza and its safety is unclear.
- Z Zakay-Rones et al. Inhibition of several strains of influenza virus in vitro and reduction of symptoms by an elderberry extract (Sambucus nigra L.) during an outbreak of influenza B Panama. J Altern Complement Med 1995; 1:361.
- C Krawitz et al. Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses. BMC Complement Altern Med 2011; 11:16.
- RS Porter and RF Bode. A review of the antiviral properties of black elder (Sambucus nigra L.) products. Phytother Res 2017; 31:533.
- Z Zakay-Rones et al. Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections. J Int Med Res 2004; 32:132.
- L Holst et al. Echinacea and elderberry-should they be used against upper respiratory tract infections during pregnancy? Front Pharmacol 2014; 5:31.
- Antiviral drugs for treatment and prophylaxis of seasonal influenza. Med Lett Drugs Ther 2019; 61:1.