Shrubs in the Sambucus genus are found globally, and their traditional use has been documented in the Americas, Africa, Europe, and the Middle East, including treatments for infections,^[22][23] ophthalmological issues,^[24] benign prostatic hyperplasia,^[25] and a broad range of other conditions.^[26]

Indigenous peoples of the Americas have also been known to use elderberry leaves for medicinal purposes.^[1] More than 60 different Indigenous peoples of the Americas, notably the Iroquois, Cherokee, Paiute, Thompson/Ntlakyapamuk, and Kawaiisu tribes, have used elderberry as a traditional treatment for a total of nearly 50 recorded conditions and ailments. The most common uses for elderberry by First Nations include as an emetic, dermatological aid, gastrointestinal aid, fever reducer, laxative, pain reliever, gynecological aid, and cold remedy.^[27]

Thus far, the evidence is mixed. The strongest evidence to date is for reduction of cold/respiratory illness symptom severity and duration (in doses of 175–600 mg/day over 2-16 days). However, there is no strong evidence to suggest that elderberry can reduce the risk of contracting a cold or viral infection.^{[4][11][12][28]} In terms of cold prevention under stressful circumstances, a single RCT compared elderberry extract to a placebo when taken at 600 to 900 mg/day for 10 days prior to air travel and 4 to 5 days after. While elderberry was not significantly better than placebo at preventing colds, the elderberry group did experience milder symptoms and shorter colds.^[5][12][29] However, when elderberry was taken by both children and adults as a syrup extract (30 mL/day for people aged 12 or younger, 60 mL/day for people over 12 years over 5 days), no reduction in the duration or severity of influenza symptoms was found.^[10][30]

The COVID-19 pandemic sparked interest in elderberry for the prevention and treatment of coronaviruses.^[17][31][32] The prevailing theories for elderberry’s potential as a COVID-19 therapeutic agent consider the antioxidant activity of anthocyanins, which may either prevent viral action and/or produce anti-inflammatory cytokines to help mitigate the damage the virus can cause.^[32][31] However, these theories are based on studies of similar viruses, not the SARS-CoV-2 virus. There is still insufficient evidence to recommend elderberry for treatment or prevention of COVID-19.^[17]

Although elderberry extracts have been shown to exhibit antiviral and antimicrobial properties in vitro, clinical research is needed to establish whether elderberry exerts antiviral/antimicrobial effects against any specific pathogens in humans.^[33]

Elderberry is often touted for preservation and protection of the immune system in general.^[12][34] Some researchers believe that elderberry’s capacity for immunoregulation occurs through modulation of cytokine release and activity; indeed, three clinical studies have demonstrated that certain preparations containing elderberry extract may stimulate a healthy immune response through cytokine release and activity in healthy individuals. It should be noted, however, that these were all industry-sponsored studies of proprietary blends.^[35][36][37]

Evidence also exists to support the use of elderberry extract from the Williams elderberry, Sambucus williamsii var. coreana, for gingivitis and halitosis. When used in a mouthwash preparation for five days by healthy individuals, it reduced indicators of plaque and gingivitis,^[8] and reduced halitosis and halitosis-causing bacteria, more than placebo^[38]

Topical application of elderberry extract from the dwarf elder,Sambucus ebulus, has also been evaluated in comparison to standard of care anti-inflammatory ointments.^[7][39] In one four-week study of the effects of this elderberry extract on eczema, twice-daily topical application of the extract was found to be no better than hydrocortisone at improving eczema severity or healing rates. However, the participants using the elderberry extract had significantly higher quality-of-life scores at the end of the trial than those using the standard of care.^[7] In another four-week study of the effectiveness of this extract for knee osteoarthritis, topical application of the elderberry extract was found to be superior to 1% diclofenac gel at reducing pain and symptom severity, with minimal risk of side effects.^[39]

Finally, there is some in vitro evidence that extracts of high-anthocyanin berries, including elderberry, may serve to decrease the growth of tumors. Further human-based clinical studies are needed to confirm this evidence, though.^[40]

Another area where the benefits of elderberry are of interest is in support of cardiometabolic health outcomes. One study found that people with overweight or obesity who drank elderberry juice had higher carbohydrate and fat oxidation than those who took placebo; however, there were no differences in energy expenditure or glucose/insulin response.^[13] An observational, non-placebo-controlled study of a combination therapy of elderberry and asparagus extracts (1 mg anthocyanin, 370 mg flavonol, 150 mg hydroxycinnamate, and 19 mg saponin per day) noted a decrease in mean weight and improvements in blood pressure among its participants, but since all participants took the supplement and additionally fasted for several days, it is difficult to know whether to attribute these results to the supplementation.^[41]

A small, non-placebo-controlled study of healthy individuals noted decreases in triglycerides, total cholesterol, and LDL cholesterol, and improvements in antioxidant capacity, after 30 days of elderberry consumption (200 mL/day of an infusion of S. ebulus berries).^[42] However, when another small study randomized healthy participants to drink elderberry juice or a placebo for two weeks, no differences in triglyceride levels were seen between groups.^[9] In a third study, which randomized postmenopausal women to take elderberry or placebo for 12 weeks, no reductions in cardiovascular disease risk factors were observed in the elderberry group when compared to the placebo group.^[6]

To recap: while there have been some promising results, the evidence to date is mixed and larger randomized controlled trials are needed to confirm the existence of positive effects.