What are the health benefits of elderberry?

The small, dark purple berries of elderberry shrubs and trees have been used for centuries as a home remedy for viral illnesses like the common cold and flu. Today you can buy an array of supplements made from elderberries, including syrups, pills, lozenges, gummies, teas, and tinctures. Most of these products tout their ability to support your immune system. But what does the evidence show?

“Elderberry syrup or tea may help reduce the duration and severity of cold and flu symptoms,” says Dr. Darshan Mehta, medical and education director at the Osher Center for Integrative Health at Harvard-affiliated Brigham and Women’s Hospital. However, the evidence for these benefits is uncertain, since the studies are small and most did not compare elderberry to standard treatments, he adds.

How does elderberry affect the immune system?

Elderberries contain compounds called anthocyanins, which give dark purple, blue, and black fruits their distinct hue. These antioxidant compounds are thought to promote healthy immune function and combat inflammation. Test tube and animal studies have found that elderberry extracts contain substances that stimulate cells involved in generating an immune response. But since these effects haven’t been confirmed in people, their potential for enhancing human immune function remains unclear, says Dr. Mehta.

Interest in the purported immune-boosting powers of dietary supplements such as elderberry rose during the COVID-19 pandemic, according to a 2021 review in BMC Complementary Medicine and Therapies. The review included five randomized trials of elderberry for treating or preventing respiratory viral illnesses. Researchers concluded that elderberry supplements may help treat cold and flu symptoms, potentially shortening the duration of a cold by about two days. However, the one study examining elderberry’s ability to prevent colds was inconclusive.

Elderberry side effects and risks

Elderberry supplements appear to be relatively safe, says Dr. Mehta. In clinical trials, effects such as nausea, vomiting, or diarrhea were mild and rare. Allergic reactions are also possible. In theory, elderberry could stimulate the immune system and exacerbate autoimmune diseases such as rheumatoid arthritis, lupus, or multiple sclerosis. But there’s no documented evidence of that happening. And the 2021 review article found no proof that taking elderberry supplements overstimulates the immune system.

But anyone interested in making their own elderberry syrup or tincture should take heed: raw or unripe elderberries and other parts of the elder tree, such as the leaves and stems, contain poisonous cyanide-producing substances. These can cause nausea, vomiting, and severe diarrhea, and large quantities of the toxin may cause serious illness. Boiling or simmering the berries for at least 20 minutes eliminates this risk.

Take-home advice about elderberry supplements

“For healthy adults, taking elderberry supplements over the short term to help relieve the symptoms of a cold or the flu is probably safe,” says Dr. Mehta. But don’t count on elderberry to ward off these illnesses. Instead, protect yourself with common-sense habits.

As is true for all dietary supplements, elderberry products are not considered medications by the FDA, so before you buy one, look for evidence of purity and quality-control testing. One example is the USP Verified Mark on the product label; it indicates the product contains the ingredients listed in the stated amounts and strengths, and is free from contaminants.

There is no recommended standard dose of elderberry; products vary widely in formulation and the amount of active ingredient they contain. Check the product label, and don’t exceed the suggested dosage. Some people recommend starting elderberry supplements within 24 to 48 hours of when your cold or flu symptoms begin.

If you take any medications, check with your doctor before using elderberry or other herbal products, as harmful interactions sometimes occur. Avoid elderberry if you’re pregnant or breastfeeding, or if you have an autoimmune disease.