Elderberry syrup rests on small, maker-funded trials, and a larger one disagreed

Key takeaways

• In 1983, 11 people at a California gathering got sick, and 8 were flown to a hospital, after drinking juice pressed from raw elderberries along with leaves and branches².
• The early flu trials behind elderberry’s reputation were small, and a medical school professor who reviewed a 2019 analysis of them named funding by elderberry makers as its biggest risk of bias⁸.
• In a Cleveland Clinic-sponsored trial of 87 people with flu, Sambucol elderberry extract worked no better than a placebo⁹¹⁰.
• There is no good evidence that elderberry prevents or treats COVID-19, and in 2020 the Federal Trade Commission warned sellers who tied it to the coronavirus¹¹¹.
• University of Maine Extension says to refrigerate homemade syrup and use it within two weeks, freeze it for longer storage and never can it¹⁴.

On August 26, 1983, 25 members of a religious and philosophical group met at a remote spot in Monterey County, California. Staff made a drink from wild elderberries picked two days earlier².

They had crushed the berries in a press along with the leaves and branches, then mixed in apple juice, water and sugar and let it sit overnight².

Within 15 minutes of drinking it, 11 people were nauseated and vomiting. Eight were flown by helicopter to a hospital in Monterey². The one patient kept overnight had drunk five glasses, while people who drank only tea stayed well. Everyone recovered quickly².

The Centers for Disease Control and Prevention (CDC) drew a simple lesson: elderberries may be safe to eat, especially cooked, but leaves and stems should not be crushed into juice².

Today elderberry turns up in syrups, gummies, capsules, cough syrups and multivitamins¹². Its cold-and-flu reputation rests on a handful of small trials, most of them paid for by the companies that sell the extracts⁸. A larger trial run by the Cleveland Clinic found no benefit for flu. And the old Monterey County lesson still applies: how you prepare elder matters.

Elder is a kitchen plant first, with a toxin in its raw parts

Federal health researchers describe elderberry as the fruit of black elder, Sambucus nigra, a plant that grows across Europe, North America, western Asia and North Africa¹. Its dark purple berries have a long history in folk medicine for colds and flu¹. Researchers who later tested it in Norway noted its traditional use for flu, colds and sinusitis⁴.

North America has native elders too. CDC’s 1984 report described the native western elder, Sambucus mexicana, whose ripe berries people commonly cooked into pies and jams or made into wine². It also noted older, anecdotal reports of children poisoned by a related species, Sambucus canadensis².

That detail is worth holding onto. In European and American homes, elder was a food long before it was a supplement. Cooked into jam or pie, it is still a food. A Cleveland Clinic integrative medicine doctor, Naoki Umeda, said in 2025 that he sees no harm in foods made with cooked elderberries¹³.

What’s in the berry. The deep color comes from anthocyanins, plant pigments in the polyphenol family. The capsules used in one major trial were standardized to 15% anthocyanins and 22% polyphenols⁶.

What’s in the rest of the plant. Elder also contains sambunigrin, a cyanogenic glycoside: a sugar-bound compound that can release cyanide¹¹².

According to NCCIH, the federal government’s complementary health research center, raw or unripe berries, leaves and stems all contain these cyanide-producing substances. They can cause nausea, vomiting and severe diarrhea, and cooking eliminates the toxin¹.

CDC’s 1984 summary went further. It said the raw shrub holds a cyanide-yielding compound in many parts, from flowers and young buds to bark, leaves and roots. Young leaves carry the most, and the root is probably the most poisonous part².

One surprise from Monterey County: the patients’ blood cyanide levels were normal². Even so, how sick people got tracked how much juice they drank².

The trials behind the syrup were small, and makers paid for most

The lab start. In lab dishes, a commercial extract called Sambucol blocked several flu strains from multiplying³. Its developer, the virologist Madeleine Mumcuoglu, said substances in the berry disarm hemagglutinin, the spiky protein flu viruses use to latch onto cells⁵. Lab results show a possible mechanism, not a benefit in people.

Israel, 1993. During a flu B outbreak on a kibbutz, a farming community, a team from the Hebrew University of Jerusalem gave Sambucol or a placebo to sick residents³. About 90% of the Sambucol group were well within two to three days, compared with at least six days on placebo³. Only 27 people were analyzed⁸. Mumcuoglu was a co-author³.

Norway, 1999–2000. Sixty adults with flu symptoms for 48 hours or less took 15 milliliters of syrup or a placebo four times a day for five days⁴. Symptoms eased about four days sooner on elderberry, and the group used less rescue medicine⁴. The authors called for a larger study⁴. At the time, Sambucol’s maker was Razei Bar Industries of Israel⁵.

Australia, 2013–2014. Griffith University researcher Evelin Tiralongo enrolled 312 economy-class passengers on flights of seven hours or more⁶⁸. They took 300-milligram elderberry extract capsules: two a day (600 milligrams) for 10 days before the trip, then three a day (900 milligrams) during travel, continuing for four more days at the destination⁶.

The trial’s main goal was fewer people with cold symptoms⁶. It missed: 12 travelers caught colds on elderberry and 17 on placebo, a difference that could be chance⁷⁸. Among travelers who did get sick, the elderberry group logged 57 total cold days versus 117, with lower symptom scores, according to a trade-press summary of the paper⁷. Iprona AG, the Italian company that makes the extract, funded the study⁶⁷.

The meta-analysis. In 2019, Hawkins and colleagues pooled four trials with fewer than 200 people in all: the two Sambucol studies, a 2009 flu study and the air-travel trial⁸. Elderberry looked strongly helpful, especially for flu⁸.

A medical school professor reviewing that analysis for a clinician newsletter pointed to its weak spot. Elderberry makers funded three of the four trials. The fourth didn’t disclose funding but used a product from the company that funded the 2004 study⁸. Only one trial involved colds rather than flu⁸.

Maker funding doesn’t make a result false. But it is the same reason careful readers question drug-company trials, and it calls for the same answer: a test run by researchers who don’t sell the product.

A Cleveland Clinic flu trial found no benefit

That test came from the Cleveland Clinic. Michael Macknin of Cleveland Clinic Children’s led a randomized, double-blind trial, meaning neither patients nor staff knew who got the real product¹⁰.

The team enrolled 87 people aged 5 and older who came to an emergency department with flu⁹. They took Sambucol or a placebo for five days. Patients 13 and older took 15 milliliters four times a day, and younger children took it twice a day¹⁰.

The product came from its maker, PharmaCare Laboratories of Australia, but the Cleveland Clinic sponsored the study itself¹⁰. The protocol does not say who paid for it¹⁰. Everyone was offered a prescription for a standard flu antiviral¹⁰.

The result, published in 2020 in the Journal of General Internal Medicine⁹¹²: illness lasted almost exactly as long in both groups⁹. “It (elderberry) didn’t make any difference at all compared to placebo,” Macknin said⁹.

In a smaller slice of patients who took no other flu medicine, the elderberry group had moderate-to-severe symptoms about two days longer⁹. Subgroup results like that need confirming. The authors said their findings contradicted earlier studies and called for more research⁹.

Use	Form and dose studied	What was found	Rating
Easing flu symptoms	Sambucol syrup, 15 ml four times a day for 5 days410	Faster relief in two small maker-linked trials; no benefit in a larger independent one489	Promising but early (contested)
Avoiding colds on long flights	Extract capsules, 600 to 900 mg a day for about two weeks6	No fewer colds; shorter, milder colds among those who got sick7	Promising but early
Preventing or treating COVID-19	No good human studies1	No good evidence	Not enough evidence
Heart health, blood sugar, skin, cancer	Test-tube studies13	Human research still needed	Not enough evidence
Drinking juice pressed from raw berries with leaves and stems	A documented group poisoning2	Vomiting, cramps, hospital care	Evidence says no, or unsafe

For how elderberry compares with other immune products, see “Your immune system works more like a team than a volume knob, and some habits help it.”

COVID-19 claims drew federal warning letters

In the spring of 2020, elderberry was swept into coronavirus marketing. NCCIH says there is no good evidence for using it against COVID-19, and that the FDA and the Federal Trade Commission (FTC) acted against companies making unsupported claims¹.

One example: on May 1, 2020, FTC staff wrote to a Philadelphia herb seller. Its “Corona Virus Protocol” included a formula with elderberry and four other herbs, sold “For Corona Virus or SARS,” with doses for prevention and for active infection¹¹.

The FTC said no competent and reliable scientific evidence backed the claims. It told the company to stop and to report its fixes within 48 hours¹¹. A warning letter is a warning, not a court ruling.

A different worry ran the other way. The professor who reviewed the 2019 analysis advised skipping elderberry during the pandemic, because lab work suggests it may raise cytokines, the immune signals behind the runaway inflammation of severe COVID-19⁸. That was one expert’s precaution, not a documented harm, and NCCIH’s fact sheet does not mention it¹.

Who should skip elderberry or check first

• Anyone tempted by raw berries. Raw or unripe berries, leaves and stems can cause nausea, vomiting and severe diarrhea. Eat elderberries only cooked¹¹³.
• Children. A Children’s Mercy Kansas City pediatrician and pharmacist note that cooking removes the toxin, but it may be hard to know whether a home batch or an unregulated product was cooked properly¹². They urge parents to ask the child’s clinician first¹².
• Autoimmune disease or immune-suppressing drugs. The same Children’s Mercy experts say elderberry should not be used by these patients¹². Umeda also says people who are immunocompromised should avoid elderberry supplements, which he worries could overstimulate the immune system¹³. NCCIH’s fact sheet does not address either group¹.
• Pregnancy and breastfeeding. Little is known about safety¹. Umeda advises avoiding supplements out of caution¹³.
• Diuretics (“water pills”). Umeda says elderberry acts as a natural diuretic, so combining it with these drugs could leave you dehydrated¹³. This caution comes from one clinician; NCCIH does not list it¹.
• Diabetes. A lab study hinted at effects on blood sugar and insulin, but human studies are still needed¹³. Syrups also carry sugar: the University of Maine recipe adds half a cup of honey to about two cups of syrup¹⁴.
• Combination products. Many elderberry products also contain echinacea, which may change how the liver processes certain drugs¹². NCCIH advises talking with your provider before using elderberry if you take any medicine¹.

When to get help. Shortness of breath or hives after elderberry can signal an allergy and needs medical care, and severe symptoms need emergency care¹³. Call 911 for trouble breathing.

Children’s Mercy also reminds families that the flu vaccine is recommended for every child over 6 months¹². Elderberry is not a substitute.

How to choose a store-bought product

There is no standard dose of elderberry. Strength varies across syrups, juices, lozenges and tinctures, and a “pure” product may still contain preservatives, binders or stabilizers¹³. Umeda suggests choosing third-party tested products¹³.

Quality is an open problem. In 2022, the trade magazine Nutritional Outlook reported that less reputable suppliers may color products with black rice or black bean, or bulk them up with grape juice extract or peanut skins⁷. That is a trade-press report, not a published lab finding, but it is a reason to buy from makers who test and name their extract.

Label check. Look for the Latin name Sambucus nigra and the word “fruit” or “berry.” Look for the amount of extract per serving, not just a “proprietary blend.” Note any added echinacea or other herbs, and check the sugar if you have diabetes.

Making syrup at home: a safer-batch checklist

Many natural-health families like making their own syrup. It lets you know exactly what went in. It also puts the safety steps in your hands. This checklist draws on University of Maine Extension, NCCIH and CDC.

1. Start with fully ripe, dark berries. Pick out every green berry, stem and leaf before you cook or press anything¹²¹⁴.
2. Be sure of the plant. If you forage, have an experienced local expert confirm the species before you harvest. “How experts tell deadly plants from their edible look-alikes” explains how.
3. Never use raw juice. Elderberries and their juice should not be eaten raw¹⁴.
4. Cook it down. The Maine Extension recipe, adapted from University of Illinois Extension, uses 1 cup of dried berries, or 2 cups of fresh or frozen, to 4 cups of water. Bring it to a boil, then lower the heat and let it cook down to roughly half its volume¹⁴.
5. Strain well. Use a fine-mesh sieve and a jar sterilized in boiling water for 10 minutes¹⁴.
6. Cool before sweetening. Add honey only after the syrup cools¹⁴. CDC says never to feed honey, or products made with it, to a child younger than 1 year, because honey can carry the bacteria that cause botulism¹⁵. Honey-based home remedies and their safety rules are covered in “Honey dressings speed burn healing, and home honey remedies need their own rules.”
7. Refrigerate and date it. Use refrigerated syrup within two weeks¹⁴.
8. Freeze for longer. Frozen syrup keeps its quality for 6 to 8 months¹⁴.
9. Don’t can it. Several elderberry varieties tested at or above pH 4.6, the cutoff for safe boiling-water canning, and Maine Extension says more research is needed before safe canning recipes exist¹⁴.

Questions readers ask

The bottom line

Elderberry has deep roots in European and American kitchens, and a few small trials suggested it might ease flu and colds. But most of those trials were funded by the makers, and the one larger, clinic-sponsored flu trial found no benefit. The honest rating is promising but contested.

If you use it, treat it as a cooked food and a modest helper, not a replacement for flu vaccines or antivirals. Never drink raw juice, keep leaves and stems out of the pot, refrigerate homemade syrup for no more than two weeks, and check with a clinician first for children, pregnancy and immune conditions.

Related reading

• Your immune system works more like a team than a volume knob, and some habits help it
• Who paid for the study matters, even when the science is real
• Honey dressings speed burn healing, and home honey remedies need their own rules
• Nature makes both medicine and deadly poison, and respecting it means telling them apart
• Echinacea came from the prairie and barely touched colds in big trials

Sources

1. National Center for Complementary and Integrative Health. “Elderberry.” NIH, updated November 2024. nccih.nih.gov
2. Centers for Disease Control and Prevention. “Poisoning from Elderberry Juice — California.” Morbidity and Mortality Weekly Report, 1984;33(13):173. cdc.gov
3. Zakay-Rones Z, Varsano N, Zlotnik M, et al. “Inhibition of Several Strains of Influenza Virus in Vitro and Reduction of Symptoms by an Elderberry Extract (Sambucus nigra L.) during an Outbreak of Influenza B Panama.” Journal of Alternative and Complementary Medicine, 1995;1(4):361-369 (Hebrew University record). cris.huji.ac.il
4. Zakay-Rones Z, Thom E, Wollan T, Wadstein J. “Randomized Study of the Efficacy and Safety of Oral Elderberry Extract in the Treatment of Influenza A and B Virus Infections.” Journal of International Medical Research, 2004;32(2):132-140 (Hebrew University record). cris.huji.ac.il
5. NutraIngredients (trade press). “Black Elderberry Extract May Reduce Flu Symptoms.” December 12, 2003. nutraingredients.com
6. Australian New Zealand Clinical Trials Registry. “Investigating the Effectiveness of Elderberry Capsules in the Prevention of Upper Respiratory Symptoms Associated with Long Distance Travel” (ACTRN12612001301853). Registered 2012. anzctr.org.au
7. Nutritional Outlook (trade press). “Elders & Betters: Elderberry Research Is Validating the Hype.” March 4, 2022. nutritionaloutlook.com
8. Selfridge. “Black Elderberry Supplementation for Upper Respiratory Infection Symptoms” (review of Hawkins J, Baker C, Cherry L, Dunne E, Complementary Therapies in Medicine, 2019;42:361-365). Relias Media, Integrative Medicine Alert, May 1, 2020. reliasmedia.com
9. Cleveland Clinic Newsroom. “Does Elderberry Reduce Severity and Duration of Flu?” (on Macknin M, et al., Journal of General Internal Medicine, 2020). Cleveland Clinic, 2021.
10. Cleveland Clinic Foundation. “Phase IV Study Evaluating the Safety and Clinical Efficacy of Elderberry Extract in Patients with Influenza: A Randomized, Double-Blind Placebo-Controlled Trial,” protocol and statistical analysis plan (NCT03410862). ClinicalTrials.gov. cdn.clinicaltrials.gov
11. Federal Trade Commission. Warning letter to Crescent Moon Herbals, LLC, regarding COVID-19 claims. May 1, 2020. ftc.gov
12. Goodwin EJ, Yoder A. “Elderberry: Is the Herbal Remedy Safe for Kids?” State-of-the-Art Pediatrics, Children’s Mercy Kansas City, February 2021.
13. Cleveland Clinic Health Essentials. “What Elderberries Can (and Can’t) Do for Your Health” (with Naoki Umeda, MD). November 26, 2025. health.clevelandclinic.org
14. McCarty K. “How to Make and Preserve Elderberry Syrup Safely.” University of Maine Cooperative Extension, February 20, 2025. extension.umaine.edu
15. Centers for Disease Control and Prevention. “Botulism Prevention.” Updated February 26, 2026. cdc.gov