What are the health benefits of elderberry?

Elderberry syrup or tea may help reduce the duration and severity of cold and flu symptoms. But the evidence for these benefits is uncertain, since the studies are small and most did not compare elderberry to standard treatments. Claims that elderberry products can prevent viral infections or boost immunity are unproven. Elderberry supplements appear to be relatively safe; in clinical trials, effects such as nausea, vomiting, or diarrhea were mild and rare.