Elderberry is sold for all-winter immunity, but its main flu trials lasted days

Key takeaways

• In 2020, elderberry sales in mainstream U.S. stores topped $275 million, up 150% in one year, making it the best-selling herbal supplement ingredient there¹.
• The small flu trials behind its reputation gave elderberry for three to five days to people who were already sick, and a 2021 review found it may not lower your chance of catching a cold⁶⁷.
• In a 2001 lab-dish study, an elderberry extract raised one inflammatory signal nearly 45-fold in donated human immune cells, yet the 2021 review found no evidence that elderberry overstimulates the immune system in people⁷⁸.
• In 2020, the FDA and the Federal Trade Commission jointly warned sellers of an “Elderberry Elixir” and an elderberry syrup over COVID-19 claims⁴⁵.
• Raw or unripe berries, leaves and stems can make you sick, red elderberry may be more toxic, and Poison Control is at 1-800-222-1222 around the clock³¹⁰¹².

In 2020, elderberry outsold every other herbal supplement ingredient in mainstream U.S. retail stores. Sales there topped $275 million, up 150% from 2019, according to the American Botanical Council’s yearly market report, which drew on retail sales data¹. Natural-food stores added another $54 million¹.

The council is a nonprofit that describes itself as member-supported, and businesses can sign on as supporting members¹⁴. Its founder, Mark Blumenthal, tied the surge to people suddenly wanting to shore up their immune systems¹. He also noted that little scientific evidence supports herbs for preventing or treating COVID-19².

Some sellers pitched elderberry as everyday protection⁴⁵. One Ohio maker promoted its elderberry syrup in August 2020 as a way to keep up healthy immunity⁵.

The research tested something narrower. In the small flu trials that built elderberry’s reputation, people who were already sick took it for three to five days⁶. A 2021 systematic review found that elderberry may not lower your chance of catching a cold at all⁷.

Meanwhile, a worry spread in the other direction: that elderberry might rev up the immune system enough to feed a “cytokine storm,” the runaway inflammation of severe COVID-19⁷.

This article looks at elderberry as an immune product: what the claims mean, what the cytokine question rests on, which elders are safe and how to use it if you choose to. Our earlier article, “Elderberry syrup rests on small, maker-funded trials, and a larger one disagreed,” covers each trial, its funding and homemade syrup in detail.

“Immune support” sold the boom, and regulators drew the line at COVID-19

Elderberry’s rise started before the pandemic. Its mainstream sales had more than doubled each year since 2018, a trade report on the market data noted². Then 2020 poured fuel on it.

Federal regulators didn’t object to elderberry itself. They objected when sellers said it could prevent or treat COVID-19.

• April 9, 2020. The Food and Drug Administration (FDA) and the Federal Trade Commission (FTC) sent a joint warning letter to an Ohio company selling an “Elderberry Elixir,” an “Immune Support Collection” and other products⁴. The company had suggested that strengthening the immune system naturally could help families fend off the coronavirus⁴.
• October 23, 2020. The two agencies warned another Ohio seller over its “Elderberry, Honey & Propolis Syrup.” Its social media posts promoted the syrup for healthy immunity and pointed to propolis against COVID-19⁵.

In both letters, the FDA said the products were unapproved new drugs, because they were promoted to prevent or treat a disease⁴⁵. Each company had 48 hours to explain how it would fix the problem⁴⁵. A warning letter is a warning, not a court ruling.

The National Center for Complementary and Integrative Health (NCCIH), a federal research agency, confirms that the FDA and FTC acted against companies making unproven COVID-19 claims for elderberry³. Memorial Sloan Kettering Cancer Center’s herb experts note that the FDA has also warned makers over claims that elderberry treats flu, diabetes and AIDS⁶.

General wording like “supports immune health” follows different rules. “Why supplement labels say ‘supports’ and never say ‘cures'” explains them, and a later article in this series looks at immune claims and immune tests in depth.

What the trials tested: short courses in people already sick

The core human evidence is thin and short.

In two small flu trials summarized by Memorial Sloan Kettering, 60 and 40 patients took elderberry within a day or two of their first symptoms⁶. One group took 15 ml of juice four times a day for five days. The other took 60 ml of a standardized extract a day for three days⁶. In both, the elderberry group recovered faster than the placebo group⁶.

Those early trials were small, and our earlier elderberry article documents the makers’ role in funding them.

In 2021, researchers published a systematic review of five randomized trials of elderberry for viral respiratory illness⁷. They judged every finding uncertain⁷:

• Avoiding colds: no clear protection.
• Colds already underway: possibly shorter and milder.
• Flu: possibly shorter.

NCCIH’s 2024 fact sheet says preliminary research suggests elderberry may relieve cold and flu symptoms, with no good evidence for COVID-19³. Memorial Sloan Kettering’s experts describe a lack of strong data for colds and flu and say its long-term safety hasn’t been determined⁶.

That leaves a gap between the shelf and the studies. In the sources we reviewed, no trial tested daily elderberry through a whole cold season to see whether it prevents illness. A daily gummy from October to March is a choice some families make, not a tested plan.

Boost or storm? What elderberry does to immune signals

Cytokines are chemical messages immune cells use to call for help and turn up inflammation. They’re vital in an infection. A harmful flood of them is what people mean by a cytokine storm⁷.

Elderberry’s cytokine story starts in a 2001 lab study. Researchers took monocytes, a type of white blood cell, from 12 healthy donors and exposed them to four Sambucol elderberry products⁸.

The elderberry extract raised four inflammatory cytokines by 2 to 45 times. One of them, called TNF-alpha, jumped 44.9-fold⁸. For comparison, a bacterial toxin that labs use to rouse immune cells raised the same signals only 3.6 to 10.7 times⁸.

The authors read that as good news. They concluded the product activated the healthy immune system⁸.

In 2020, lab findings like these looked like a warning. People asked whether elderberry might make an overreacting immune system worse during COVID-19. The 2021 review team set out partly to answer that question⁷.

What they found in people⁷:

• No study had looked at actual inflammatory illness in people taking elderberry.
• Three studies took blood cells from people after they used elderberry and measured cytokine output.
• The markers shifted somewhat, but the change seemed to shrink the longer people kept taking it.
• One small study pitted elderberry against the anti-inflammatory drug diclofenac. Over time, elderberry lowered cytokines about as much as the drug or less.

The reviewers found nothing to suggest that elderberry pushes the immune system into overdrive. They also called the evidence on both benefits and harms uncertain⁷.

Memorial Sloan Kettering’s summary shows why both stories could take hold. Its list of proposed ways elderberry works includes both raising cytokine output and blocking an inflammation switch called NF-kB⁶.

The lesson goes beyond one berry. Cells in a dish are not a person, and a healthy immune system is about balance, not volume. “Your immune system works more like a team than a volume knob, and some habits help it” explains why.

The elderberry claims, rated

Claim	What the evidence shows	Rating
Eases flu symptoms when started early	Small three- to five-day trials found faster relief; review rates it uncertain67	Promising but early
Shortens or eases colds	May help; uncertain7	Promising but early
A daily dose all winter prevents colds	May not lower the risk of a cold; no season-long trial found7	Not enough evidence
Prevents or treats COVID-19	No good evidence3	Not enough evidence
“Boosts” immunity in healthy people	Big jumps in lab dishes; human marker changes may fade78	Not enough evidence
Sets off a cytokine storm	No evidence of overstimulation in people7	Not enough evidence
Raw berries, leaves or stems are safe to eat	Documented poisonings; cooking removes the toxin311	Evidence says no, or unsafe

Not every elder is the same plant

NCCIH describes elderberry as the fruit of the European or black elder, Sambucus nigra³. The products in the lab and flu studies above were black elderberry preparations⁶⁸.

North America has its own elders, and several are now grouped under the same species⁹¹⁰:

• American elderberry (Sambucus nigra subsp. canadensis) is a many-stemmed shrub. The European elder grows as a small tree⁹. The University of Missouri leads breeding of fruit varieties, and growers sell berries to processors serving the health market⁹.
• Blue elderberry (S. nigra ssp. cerulea) is reliably acidic, unlike American elderberry, and that acidity decides which canning methods are safe¹⁰.
• Red elderberry (Sambucus racemosa) belongs to another species entirely. Little research exists on it, but Oregon State University’s food-safety specialists think its toxin levels may run higher, concentrated in the seeds, and tell home preservers to leave it out of food¹⁰.

The 1983 California poisoning that CDC investigated involved a western elder. People got sick after drinking juice pressed from raw berries crushed with leaves and branches¹¹.

Reading a product. Look for the Latin name, the part used (fruit or berry, not flower, unless that’s what you want) and the amount of extract per serving. Memorial Sloan Kettering advises choosing products checked by an independent testing program⁶. “Supplement Seals Test Different Things. Know Which One You’re Trusting” explains how to verify a seal, and “Some herbal pills hide prescription drugs, and others swap out the herb” covers how often elder berry extracts are stretched with other pigments.

Check the sugar. Syrup is sweet by definition. Oregon State’s tested elderberry syrup recipe uses 3½ cups of sugar for 2½ cups of juice, more sugar than juice¹⁰. If you have diabetes, read the Nutrition or Supplement Facts panel for sugar per serving.

Using elderberry safely, as a food or a remedy

Never eat it raw. The problem is a group of natural compounds that release cyanide. According to NCCIH, they’re found in unripe or uncooked berries and in the leaves and stems, and they can cause vomiting, nausea and severe diarrhea. A large dose can make someone seriously ill³.

Heat solves the problem: NCCIH says cooking destroys the toxin³. Oregon State’s specialists add two steps. Pick out stems and leaves, which carry higher toxin levels, and soak dried berries in water or juice before cooking them¹⁰.

If someone eats the wrong part. Call Poison Control at 1-800-222-1222. The line works 24 hours a day from anywhere in the U.S., and you can call even when it isn’t an emergency¹².

For a plant poisoning, MedlinePlus says to call 911 or Poison Control¹². Severe cyanide poisoning can cause dizziness, seizures and death¹⁰, so call 911 for signs like those¹².

Medicines. NCCIH advises talking with a health care provider before using elderberry if you take any medicine³. Memorial Sloan Kettering flags possible added effects with diabetes drugs (blood sugar dropping too low), diuretics and laxatives, though these haven’t been proven in people⁶. Some cold products pair elderberry with echinacea. In lab tests, one such blend slowed a drug-processing liver enzyme, mostly because of the echinacea⁶. “How to pick an echinacea product that was tested, since most never were” explains that interaction.

Pregnancy and breastfeeding. Little is known about safety, NCCIH says³.

Children. NCCIH’s fact sheet doesn’t address children³. Ask your child’s clinician, and see our earlier elderberry article for pediatric cautions. Many syrups contain honey. CDC’s cold advice suggests honey for coughs in children 1 year and older¹³, and “Honey dressings speed burn healing, and home honey remedies need their own rules” explains why babies are different.

Immune conditions. NCCIH doesn’t address autoimmune disease or immune-suppressing drugs³. The theoretical concern comes from lab studies showing immune activation⁸, while the 2021 review found no overstimulation in people⁷.

If you have an autoimmune disease or a transplant, ask the specialist who manages your medicines. A later article in this series covers supplement cautions for autoimmune conditions.

Allergy. Allergic reactions to elderberry have been reported⁶. CDC lists trouble breathing or fast breathing among the reasons to get medical care during a cold¹³.

The elderberry safety and evidence card

Question	Short answer	Source
Will a daily gummy keep me from catching colds?	Unproven; the 2021 review found it may not lower your risk	7
Does it help once I’m sick?	Maybe a little, if started early; the evidence is uncertain	67
Can it prevent or treat COVID-19?	No good evidence; regulators warned sellers who said so	345
Could it overstimulate my immune system?	Lab dishes showed big cytokine jumps; a review found no evidence of it in people	78
Can I eat berries straight off the bush?	No; cook them and remove stems and leaves	310
Is red elderberry OK to use?	No; food-safety experts advise against it	10
Someone ate raw berries, leaves or stems. Now what?	Call Poison Control at 1-800-222-1222; call 911 for a seizure	1012
I’m pregnant or breastfeeding. Is it safe?	Little is known; ask your clinician	3
I take prescription medicines. Any concerns?	Ask about diabetes drugs, diuretics, laxatives and echinacea blends	36
Can my 9-month-old have syrup made with honey?	No; CDC’s cold advice limits honey to children 1 year and older	13
How long is it safe to take?	Long-term safety hasn’t been determined	6
When does a cold need a clinician?	Trouble breathing, dehydration, fever over 4 days or symptoms over 10 days	13

The old way of eating elderberries is the safe way

Long before elderberry came in gummies, it came in jelly jars. Tennessee’s extension service lists jellies, jams, syrups and desserts among the fruit’s uses, plus wine from the fruit and flowers⁹.

That kitchen habit carries a lesson for natural-health readers. Ripe fruit, cooked, with the stems and leaves picked out, is exactly what today’s safety advice asks for³¹⁰.

Treating elderberry as a cooked food you enjoy in season, rather than a pill you must take every day, honors that tradition. It also fits the evidence better. Nothing in the research shows that more elderberry, taken longer, buys more protection.

None of this replaces care for a serious illness. CDC’s warning signs for a cold, from trouble breathing to a fever that lasts more than four days, apply whether or not elderberry is in your cupboard¹³.

Questions readers ask

The bottom line

Elderberry’s boom ran on the idea of daily immune support, but the research tested something smaller: mostly a few days of syrup or extract for people already sick, with uncertain results. No study in people has shown the feared cytokine storm, and none has shown a proven immune boost.

If you use elderberry, treat it as a cooked food or a short-term remedy. Never eat raw berries, leaves or stems, avoid red elderberry, check the sugar, ask about your medicines and keep Poison Control’s number handy.

Keep exploring: how to choose echinacea.

Related reading

• Elderberry syrup rests on small, maker-funded trials, and a larger one disagreed
• How to pick an echinacea product that was tested, since most never were
• Your immune system works more like a team than a volume knob, and some habits help it
• Why supplement labels say ‘supports’ and never say ‘cures’
• How experts tell deadly plants from their edible look-alikes

Sources

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2. New Hope Network (trade press). “US Herbal Supplement Sales Increase by Record-Breaking 17.3% in 2020.” September 17, 2021. newhope.com
3. National Center for Complementary and Integrative Health. “Elderberry.” NIH, last updated November 2024. nccih.nih.gov
4. U.S. Food and Drug Administration and Federal Trade Commission. Joint warning letter to Earthley Wellness dba Modern Alternative Mama LLC. April 9, 2020. ftc.gov
5. U.S. Food and Drug Administration and Federal Trade Commission. Warning letter to Beepothecary LLC (MARCS-CMS 608383). October 23, 2020. fda.gov
6. Hou YN, Gubili J (Memorial Sloan Kettering Cancer Center). “Elderberry.” The ASCO Post, Integrative Oncology, July 10, 2020. ascopost.com
7. Wieland LS, Piechotta V, Feinberg T, Ludeman E, Hutton B, Kanji S, Seely D, Garritty C. “Elderberry for Prevention and Treatment of Viral Respiratory Illnesses: A Systematic Review.” BMC Complementary Medicine and Therapies, 2021;21(1):112 (University of Ottawa and University of Cologne repository records). ruor.uottawa.ca and pubmed.ncbi.nlm.nih.gov
8. Barak V, Halperin T, Kalickman I. “The Effect of Sambucol, a Black Elderberry-Based, Natural Product, on the Production of Human Cytokines: I. Inflammatory Cytokines.” European Cytokine Network, 2001;12(2):290-296 (PubMed record, PMID 11399518, as reproduced in a saved copy). accurateclinic.com
9. Rose M, Bumgarner N. “Elderberries for Tennessee Gardens and Landscapes” (D 234-A). University of Tennessee Institute of Agriculture, Fall 2024. doi.org
10. Oehler N, Waite-Cusic J, Hibbard-Swanson J. “Play It Safe When Preserving Elderberries” (EM 9446). Oregon State University Extension Service, November 2024. extension.oregonstate.edu
11. Centers for Disease Control and Prevention. “Poisoning from Elderberry Juice — California.” Morbidity and Mortality Weekly Report, 1984;33(13):173. cdc.gov
12. MedlinePlus Medical Encyclopedia. “Rhubarb Leaves Poisoning” (poison control instructions), reviewed October 14, 2025; and Health Resources and Services Administration, Poison Help, “Plants,” updated April 15, 2025. medlineplus.gov and poisonhelp.hrsa.gov
13. Centers for Disease Control and Prevention. “Preventing and Managing the Common Cold.” CDC fact sheet, 2026. cdc.gov
14. Candid (GuideStar). “American Botanical Council” nonprofit profile (describes ABC as “a nonprofit, member-supported organization”), accessed October 2026; and RAW Forest Foods, “Partnership with the American Botanical Council” (company page, used only to show that businesses join ABC as supporting members), accessed October 2026. guidestar.org and rawforestfoods.com