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Quick answer
Elderberry syrups and lozenges are widely sold to ease colds and flu. A handful of small studies found that people taking elderberry extract recovered a couple of days sooner. The evidence is limited: studies were small, often funded by manufacturers, and larger, independent trials are lacking.
Commercial elderberry products made from cooked, ripe berries are generally safe for short-term use. Raw or unripe berries, leaves, bark and stems contain compounds that can release cyanide and cause nausea, vomiting and diarrhoea.
What elderberry is
Elderberries are the dark purple fruit of the European elder tree (Sambucus nigra). They are rich in anthocyanins, the pigments that give them their colour, along with other polyphenols. In lab studies, elderberry extracts can block some influenza viruses from entering cells and may influence immune signalling.
What the research says
- Flu: two small early trials of a commercial elderberry syrup during flu outbreaks reported that people taking it recovered about 3 to 4 days faster than those on placebo. Both were small and funded by the manufacturer.
- Colds in air travellers: a 2016 Australian trial of over 300 people flying long-haul found that elderberry extract did not significantly reduce the number of colds but appeared to shorten their duration by about two days and reduce severity.
- Meta-analysis: a 2019 review pooling a few trials concluded elderberry substantially reduced upper respiratory symptoms, but it included only four small studies.
- A larger trial of elderberry in adults with flu seen in emergency departments found no benefit over placebo.
Overall, elderberry may help some people feel better slightly sooner, but the evidence is not strong enough to rely on, especially for flu.
How people use it
- Use commercial products made from cooked, ripe berries, from a reputable manufacturer, and follow the dose on the label. Typical products are taken several times a day for up to 5 days, starting within 48 hours of symptoms.
- Homemade syrup: if you make your own, use only fully ripe berries, remove all stems and leaves, and cook them thoroughly (simmer for at least 30 minutes). Cooking destroys the harmful compounds.
- Don't use it for prevention long-term; there is little evidence for this and long-term safety is unknown.
Many elderberry syrups are high in sugar. For children, and for teeth in general, take them with meals and rinse with water afterwards, or brush.
Possible side effects and interactions
When properly prepared, elderberry is usually well tolerated for short periods. Side effects can include:
- Nausea, vomiting or diarrhoea (more likely with raw or poorly prepared berries)
- Allergic reactions in sensitive people
Potential interactions (mostly theoretical, based on how elderberry acts):
- Immunosuppressant medicines (for example, after a transplant or for autoimmune disease): elderberry may stimulate the immune system
- Diabetes medicines: may slightly lower blood sugar
- Diuretics and laxatives: elderberry may have mild diuretic and laxative effects
Who should avoid it
- People with autoimmune diseases (such as rheumatoid arthritis, lupus or multiple sclerosis) or taking immunosuppressants, unless their doctor agrees
- Pregnant or breastfeeding women, due to lack of safety data
- Young children, unless using a product specifically labelled for their age and agreed with a doctor
- People at high risk from flu should not use elderberry instead of antiviral medicine
Flu needs more than a home remedy for some people
People at higher risk of flu complications should contact a doctor early, ideally within 48 hours, because antiviral medicines work best when started early. This includes:
- Adults over 65 and young children, especially under 2
- Pregnant women
- People with asthma, COPD, heart disease, diabetes, kidney or liver disease
- People with weakened immune systems
The annual flu vaccine remains the most effective way to prevent flu.
When to see a doctor
Seek medical help if you have:
- Difficulty breathing, shortness of breath, or chest pain
- Confusion, severe drowsiness or difficulty waking
- Persistent high fever, or fever that returns after improving
- Severe weakness, muscle pain or not passing urine
- Symptoms that improve and then get worse, which can signal a secondary infection such as pneumonia
- A child who is breathing fast, has blue lips, is not drinking, or has a rash with fever
Frequently asked questions
Does elderberry boost the immune system?
Lab studies show elderberry can influence immune signals, but that does not prove it improves immune protection in people. Good sleep, nutrition and vaccination are proven ways to support immunity.
Is elderberry safe for children?
Some products are made for children, but evidence on effectiveness and safety in children is very limited. Check with your doctor or pharmacist and never give homemade preparations to children.
Can I take elderberry with Tamiflu?
There is no known interaction, but check with your doctor or pharmacist. Elderberry should never replace prescribed antiviral treatment.
How long can I take elderberry?
Studies used it for up to about 5 days during an illness. Long-term safety is unknown.
References
- National Center for Complementary and Integrative Health (NCCIH). European elder. https://www.nccih.nih.gov/health/european-elder
- Tiralongo E, Wee SS, Lea RA. Elderberry supplementation reduces cold duration and symptoms in air-travellers: a randomized, double-blind placebo-controlled clinical trial. Nutrients, 2016.
- Hawkins J, et al. Black elderberry supplementation effectively treats upper respiratory symptoms: a meta-analysis of randomized, controlled clinical trials. Complementary Therapies in Medicine, 2019.
- US Centers for Disease Control and Prevention. Poisoning from elderberry juice, California, 1983. Morbidity and Mortality Weekly Report, 1984.