Herbs for Cold and Flu Season: What the Evidence Shows for Elderberry, Echinacea, Andrographis, Garlic, and Ginger

Every autumn, pharmacy shelves fill with elderberry syrups, echinacea teas, and herbal blends promising to help people get through cold and flu season. Lists of “powerful herbs” for flu circulate widely online. Some of these herbs have been studied in randomized trials, and a few show modest benefits for symptoms. None has been shown to prevent influenza the way vaccination does or to replace antiviral medicines for people at high risk.

This guide reviews the evidence for five of the most popular herbs, explains how colds and flu differ, covers safety and drug interactions, and puts herbal remedies in context alongside the measures that most reliably reduce the burden of respiratory infections.

Do herbs like elderberry and echinacea help with colds and flu? The evidence is modest at best. Some herbs may slightly shorten or ease colds for certain people, but results are mixed and the research is often weak. Elderberry and zinc have the most support for colds; echinacea and garlic are inconsistent. None reliably treats the flu, for which vaccination and antiviral drugs are the proven tools. Supplement quality also varies widely. Root powders such as maca are another popular herbal supplement with mixed evidence. Multi-herb formulas are also marketed for other conditions, including a Tibetan blend sold to prevent root canals.

What Is the Difference Between a Cold and the Flu?

Colds are milder and caused by many viruses, while influenza is a specific, often more severe illness; this matters because the flu has proven treatments and vaccines, whereas colds do not. The common cold and influenza are both respiratory infections, but they differ in cause and severity. Colds are caused by many viruses, most often rhinoviruses, and usually bring a runny or stuffy nose, sneezing, sore throat, and mild fatigue. Influenza is caused by influenza viruses and typically starts more suddenly, with fever, chills, body aches, headache, extreme fatigue, and cough. Flu can lead to pneumonia, hospitalization, and death, particularly in older adults, young children, pregnant people, and people with chronic health conditions.

Most studies of herbal remedies have focused on colds or general upper respiratory symptoms rather than laboratory-confirmed influenza. That distinction matters: a remedy that modestly eases a stuffy nose is not necessarily effective against influenza, and no herb has been shown to prevent serious flu complications.

1. Elderberry

Elderberry comes from the dark berries of the European elder tree, Sambucus nigra. Syrups, lozenges, and gummies made from elderberry extract are among the best-selling cold and flu supplements. Laboratory studies have found that elderberry extracts can inhibit influenza viruses in cell cultures, possibly by interfering with how viruses attach to cells.

Human evidence is limited but somewhat encouraging. A 2019 meta-analysis in Complementary Therapies in Medicine by Jeremy Hawkins and colleagues pooled randomized trials with a total of 180 participants and concluded that elderberry supplementation substantially reduced upper respiratory symptoms. The trials were small, several were funded by manufacturers, and they used different products, so the findings need confirmation in larger, independent studies.

The National Center for Complementary and Integrative Health notes that elderberry products may help relieve flu symptoms but that the research is limited, and it warns that raw or unripe elderberries, as well as the plant’s leaves, bark, and stems, contain compounds that can cause nausea, vomiting, and diarrhea. Properly prepared commercial products and cooked berries do not carry this risk.

2. Echinacea

Echinacea, from the purple coneflower native to North America, is one of the most studied herbal remedies for colds. Products vary widely, using different species, plant parts, and preparation methods, which complicates research.

A Cochrane systematic review summarized in a 2015 JAMA clinical evidence synopsis by Marlies Karsch-Völk and colleagues found that echinacea products did not provide meaningful benefits for treating colds, though some preventive trials suggested a small reduction in the risk of catching a cold. The authors noted that the effects, if real, were weak and that product differences make generalization difficult. NCCIH similarly describes the evidence as mixed.

Echinacea is generally well tolerated in short-term use. It can cause allergic reactions, particularly in people allergic to plants in the daisy family, such as ragweed, chrysanthemums, and marigolds.

3. Andrographis

Andrographis paniculata is a bitter herb used in traditional Indian and Chinese medicine for coughs, sore throats, and fevers. It is sold in some countries in standardized extracts, often combined with other herbs.

A 2017 systematic review and meta-analysis in PLOS ONE by Xiao-Yang Hu and colleagues included 33 randomized trials with 7,175 patients with acute respiratory tract infections. Compared with placebo, andrographis improved cough and sore throat, and it shortened time to symptom resolution and sick leave in some comparisons. However, the authors rated the overall methodological quality of the trials as poor, with many trials small and at risk of bias, and called for well-designed trials.

Andrographis may cause gastrointestinal upset, headache, and allergic reactions. It is not recommended during pregnancy, and it may interact with blood pressure, blood-thinning, and immune-suppressing medicines.

4. Garlic

Garlic has long been used as a folk remedy for colds, and its compound allicin has antimicrobial activity in laboratory studies. A 2014 Cochrane review by Elizabeth Lissiman and colleagues found only one trial meeting its criteria, with 146 participants, which reported fewer colds in the garlic group than in the placebo group over 12 weeks. The reviewers concluded there was insufficient evidence to determine whether garlic prevents or treats the common cold, since a single trial cannot support firm conclusions.

Garlic is safe in food amounts. NCCIH notes that garlic supplements can increase bleeding risk and interact with some medicines, including blood thinners and certain HIV drugs.

5. Ginger

Ginger is widely used in teas and home remedies for sore throats and congestion, and it has good evidence for some other uses, such as nausea. For colds and flu, however, there is little clinical research. NCCIH does not list colds or flu among the uses supported by evidence. A warm ginger tea with honey and lemon can be soothing and help with fluid intake, but there is no reliable evidence that ginger prevents or shortens respiratory infections.

Herb	Best evidence	Common forms	Key safety notes
Elderberry	Small trials suggest symptom relief	Syrup, lozenges, gummies	Never eat raw or unripe berries, leaves, or stems
Echinacea	Possible small preventive effect; no treatment benefit	Tea, tincture, capsules	Allergy risk in people sensitive to daisy-family plants
Andrographis	Low-quality trials suggest cough and sore throat relief	Standardized extract tablets	Avoid in pregnancy; possible drug interactions
Garlic	Insufficient evidence (one trial)	Food, capsules	Supplements may increase bleeding risk
Ginger	Little evidence for colds or flu	Tea, food, capsules	Generally safe in food amounts

What Actually Works Against the Flu?

Against influenza, the proven tools are annual vaccination and, when appropriate, prescription antiviral drugs; no herbal product reliably prevents or treats the flu. Herbal remedies are, at best, modest helpers for symptoms. The measures with the strongest evidence for reducing the burden of influenza are different. NCCIH’s overview of complementary approaches for colds and flu emphasizes that the best way to prevent the flu is to get vaccinated each year and that no complementary approach has been shown to be as effective.

Annual flu vaccination. The flu vaccine reduces the risk of illness, hospitalization, and death, and is recommended for nearly everyone six months and older, with particular importance for high-risk groups. Its effectiveness varies from year to year depending on how well it matches circulating strains, but it consistently reduces severe outcomes.

Prescription antiviral medicines. Antivirals such as oseltamivir, started early in illness, can shorten flu symptoms and are recommended for people at high risk of complications or who are severely ill. Anyone in a high-risk group who develops flu symptoms should contact a healthcare provider promptly.

Everyday prevention. Washing hands, covering coughs, staying home when sick, improving indoor ventilation, and, during peaks, wearing a mask in crowded indoor settings all reduce transmission of respiratory viruses.

Supportive care. Rest, fluids, and over-the-counter remedies for fever and aches help most people recover from uncomplicated colds and flu.

Why Is Research on Cold and Flu Herbs So Weak?

Herbal research is difficult because products vary in composition and dose, studies are often small and poorly designed, and colds resolve on their own, making modest effects hard to measure. Readers often ask why, after decades of use and study, there is still no clear answer on whether popular herbs work for colds and flu. Several features of herbal research make firm conclusions hard to reach.

Products differ widely. Two bottles labeled echinacea may contain different species, different plant parts such as roots or flowers, and different extraction methods, producing very different chemical profiles. A positive trial of one product says little about another.

Trials are often small. Many herbal trials enroll a few dozen to a few hundred participants, too few to detect modest effects reliably or to rule out chance findings.

Outcomes are subjective. Cold symptoms are usually measured by participants’ own ratings, which are sensitive to expectations. Without careful blinding, especially difficult with strong-tasting herbs, placebo effects can inflate results.

Funding and publication bias. Some trials are funded by manufacturers, and small negative studies are less likely to be published, which can make the evidence look more favorable than it is.

Colds are not the flu. Most trials study general upper respiratory symptoms rather than laboratory-confirmed influenza, so results may not apply to flu specifically.

These limitations do not mean herbs never work. They mean that modest, inconsistent benefits are what the current evidence can support, and that well-designed independent trials are still needed.

How Do I Read an Herbal Supplement Label?

Check the specific species and plant part, the standardized dose, third-party quality seals, and warnings, since supplements are loosely regulated and products differ widely in strength and purity. Scientific name and plant part. Look for the Latin name, such as Sambucus nigra fruit or Echinacea purpurea aerial parts, which helps compare products with those used in studies.

Amount and standardization. Labels should state the amount of extract per dose and, for standardized extracts, the content of key compounds.

Third-party testing seals. Independent verification programs test whether products contain what the label says and are free of specified contaminants.

Claims. Supplements cannot legally claim to treat or prevent disease. Products that promise to “cure the flu” or “boost immunity against all viruses” are making claims beyond what the evidence supports.

Added ingredients. Many elderberry gummies and syrups contain significant added sugar, and combination products may include zinc, vitamin C, or other herbs that matter for dosing and interactions.

Special Considerations for Children and Older Adults

Children are frequent targets of elderberry gummies and herbal syrups, but few herbal products have been studied adequately in young children, and appropriate doses are often unclear. Children under five, and especially under two, are at higher risk of flu complications, making vaccination and prompt medical advice particularly important. Many over-the-counter cough and cold medicines are not recommended for young children, which is one reason parents seek alternatives; honey for children over one year, fluids, rest, and saline drops are reasonable supportive measures.

Older adults face the highest risk of severe flu, hospitalization, and death. They are also more likely to take multiple medicines, increasing the potential for interactions with herbal products. For adults 65 and older, annual vaccination, with formulations designed for older adults where available, and early contact with a healthcare provider if flu symptoms develop, matter far more than any herbal remedy.

Pregnant people are at increased risk of severe flu, and flu vaccination is recommended during pregnancy to protect both the pregnant person and the newborn. Herbal remedies should be used in pregnancy only after discussion with a clinician.

Timing: When to Prepare for Flu Season

In the Northern Hemisphere, influenza activity typically begins in the fall, peaks between December and February, and can continue into spring. Health authorities generally recommend getting vaccinated in September or October when possible, since it takes about two weeks after vaccination for protection to develop. Getting vaccinated later in the season is still worthwhile while flu is circulating. Planning ahead, including knowing how to reach a healthcare provider quickly if symptoms start, helps people at high risk get antiviral treatment within the window when it is most effective.

Other Popular Remedies

Several non-herbal remedies are often used alongside herbs during cold and flu season.

Honey. A Cochrane review found honey probably reduces cough frequency in children over one year better than no treatment or placebo. It should never be given to infants under 12 months. Our guide to manuka honey and its antibacterial properties covers the evidence in more detail.

Zinc. Some studies suggest zinc lozenges started early may shorten colds slightly, but results are inconsistent and zinc can cause nausea and a bad taste. Intranasal zinc products have been linked to loss of smell and should be avoided.

Vitamin C. Regular vitamin C supplementation has not been shown to prevent colds in the general population, though it may slightly shorten their duration; taking it only after symptoms begin has shown little benefit in most studies.

Saline rinses and steam. Saltwater gargles and nasal saline rinses can ease sore throats and congestion. If using a neti pot, use distilled, sterile, or previously boiled water.

Safety and Drug Interactions

Because herbal supplements are biologically active, they can cause side effects and interact with medicines. Supplements are also regulated differently from drugs in the United States: they do not require approval before sale, and their content and quality can vary.

Tell your healthcare provider and pharmacist about any herbs you take, especially if you take blood thinners, immune-suppressing drugs, diabetes medicines, blood pressure medicines, or medicines with a narrow safety margin.

Be cautious in pregnancy and breastfeeding. Safety data for most herbal cold remedies in pregnancy are limited, and some, such as andrographis, are not recommended.

Use child-appropriate products and doses. Many herbal products have not been studied in children. Check with a pediatrician before giving them.

Watch for allergic reactions, especially with echinacea in people allergic to daisy-family plants.

Choose quality products. Look for products from reputable manufacturers with independent third-party testing for identity and contaminants.

When to Seek Medical Care

Most colds and many cases of flu can be managed at home. Seek medical care promptly if you or a family member experiences difficulty breathing or shortness of breath, chest pain or pressure, confusion, severe weakness, inability to keep fluids down or signs of dehydration, a high fever that persists or returns after improving, worsening of a chronic medical condition, or, in children, fast breathing, bluish lips, not waking or interacting normally, or a fever with a rash. People in high-risk groups who develop flu symptoms should contact a healthcare provider early, since antiviral treatment works best when started soon after symptoms begin.

A Note on “Immune Boosting”

Many herbal products are marketed as “immune boosters.” The phrase is appealing but scientifically vague. The immune system is not a single dial that can simply be turned up; an overactive immune response causes problems of its own, such as allergies and autoimmune disease. What helps the immune system function well is fairly ordinary: adequate sleep, a balanced diet with enough protein, vitamins, and minerals, regular physical activity, not smoking, managing chronic conditions, and vaccination, which trains the immune system to recognize specific pathogens.

Some herbs may influence immune activity in laboratory experiments, but that does not mean they reduce infections in healthy people. Correcting a genuine nutrient deficiency, such as low vitamin D in people who are deficient, may support immune function, but taking extra supplements when nutrient levels are adequate has not been shown to prevent colds or flu.

Comfort Measures That Help

While herbs have limited evidence, several simple comfort measures help people feel better while their bodies fight off a cold or flu. Warm drinks, including herbal teas, soothe sore throats and help maintain fluid intake. Humidified air can ease congestion and dry throats. Rest supports recovery. Saltwater gargles relieve sore throats. Over-the-counter pain relievers and fever reducers, used as directed and with attention to age restrictions such as avoiding aspirin in children and teenagers, ease aches and fever. These measures do not shorten illness much, but they make it more bearable.

What Researchers Are Studying Next

Research on herbal remedies for respiratory infections continues. Priorities include larger, independently funded randomized trials of standardized products, studies focused on laboratory-confirmed influenza rather than general symptoms, research on safety and dosing in children and older adults, and studies of potential interactions with common medicines. Laboratory work continues to explore how compounds in elderberry and other plants interact with viruses, which could eventually lead to new antiviral drugs, though such discoveries typically take many years to translate into proven treatments.

Questions to Ask Before Trying an Herbal Remedy

Is there clinical evidence for this herb for my specific symptoms, and how strong is it? Could it interact with any medicines I take, or with a condition I have? Is it safe for my age, or during pregnancy or breastfeeding? Does the product identify the species, plant part, and dose, and has it been independently tested? Am I in a high-risk group that should contact a healthcare provider about antiviral treatment instead? What will I do if symptoms worsen? Asking these questions keeps herbal remedies in their proper place: an optional addition to proven measures, not a replacement for them.

Cold and Flu Season Checklist

Schedule your flu vaccine early in the season. Stock basic supplies: a thermometer, fever reducers appropriate for each family member’s age, saline spray, honey for coughs in anyone over one year, and fluids. Know your healthcare provider’s after-hours options and whether telehealth visits are available. If you or a family member is at high risk, ask in advance how to get antiviral treatment quickly if flu symptoms start. Keep a list of medicines and supplements each person takes to check for interactions. Plan for staying home when sick, including childcare and work arrangements.

What About Combination Products?

Many cold and flu supplements combine several ingredients, such as elderberry with zinc and vitamin C, or echinacea with other herbs. Combination products make it harder to know which ingredient, if any, is responsible for a perceived benefit, and they increase the chance of side effects or interactions. Doses of individual ingredients in combinations may also differ from those tested in trials. If you choose a combination product, check the amount of each ingredient, avoid taking multiple products that contain the same ingredient, and pay particular attention to zinc, which can cause side effects at high doses and should not be used in nasal sprays.

A Word on Online Herb Lists

Lists of “powerful herbs” for flu season are popular because they offer a sense of control over illness. When reading them, look for whether claims link to clinical studies in people rather than laboratory or animal research, whether they mention side effects and interactions, and whether they encourage vaccination and medical care for high-risk people. Lists that promise herbs can replace vaccines or antivirals, or that sell products alongside the advice, deserve extra skepticism.

The Bottom Line

Herbal remedies remain popular during cold and flu season, and some have modest supporting evidence. Elderberry and andrographis may ease symptoms of upper respiratory infections, echinacea may slightly reduce the chance of catching a cold when taken preventively, and garlic and ginger have little evidence for these uses. None has been shown to prevent influenza or its serious complications. The most effective steps remain annual vaccination, everyday hygiene, early antiviral treatment for people at high risk, and supportive care. People who choose herbs should use quality products, check for interactions, and keep expectations realistic. Traditional cough remedies like osha root have little research behind them and carry look-alike risks when foraged.

When Symptoms Linger

Most colds improve within seven to ten days, though a cough can linger for a few weeks. Flu symptoms usually improve within a week, while tiredness can last longer. Symptoms that last more than ten days without improving, improve and then worsen, or come with a high fever, sinus pain, ear pain, or shortness of breath may signal a bacterial infection or complication and deserve medical attention.

Key Terms

Influenza: A respiratory illness caused by influenza viruses, generally more severe than a cold.

Antiviral medicines: Prescription drugs, such as oseltamivir, that can shorten flu illness when started early.

Standardized extract: A herbal product processed to contain a consistent amount of specific compounds.

Meta-analysis: A statistical combination of results from multiple studies.

Placebo effect: Improvement in symptoms due to expectations rather than the treatment itself.

Myths About Herbal Flu Remedies

“Natural remedies work as well as the flu shot.” No herb has been shown to prevent influenza or its serious complications the way vaccination does.

“Herbs are always safe because they are natural.” Herbs can cause side effects and interact with medicines; raw elderberries can make people sick.

“If a little helps, more is better.” Higher doses increase the risk of side effects without proven additional benefit.

“Herbal remedies can replace antivirals for high-risk patients.” They cannot. Antivirals are recommended for people at high risk of complications.

“Lab results prove an herb kills the flu virus.” Effects in cell cultures often do not translate into benefits in people.

A Sensible Plan for Cold and Flu Season

Get the annual flu vaccine and stay up to date on other recommended vaccines. Practice good hand hygiene and stay home when sick. Know your risk: if you are older, pregnant, have a chronic condition, or care for a young child, talk with your healthcare provider about what to do if flu symptoms start. If you want to try herbal remedies, choose those with at least some supporting evidence, such as elderberry for symptoms, use quality products at recommended doses, check for interactions, and expect modest effects at most. Focus on rest, fluids, and supportive care when ill.

Frequently Asked Questions

Do herbs really help with colds and the flu?

The evidence is modest at best. Some herbs and supplements may slightly shorten or ease cold symptoms for certain people, but study results are mixed and the research is often weak. Elderberry and zinc have the most support for colds, while echinacea, garlic, and others are inconsistent. None is a reliable treatment, and the flu is best handled with vaccination and antiviral drugs.

Does elderberry work for colds and flu?

Elderberry has some of the better evidence among cold and flu herbs: a few small studies suggest it may modestly shorten the duration or severity of colds and flu-like illness. However, the studies are small and not definitive, and elderberry is not a substitute for flu vaccination or antivirals. Raw or unripe elderberries are toxic and must be properly prepared.

Does echinacea prevent colds?

The evidence for echinacea is inconsistent. Some studies suggest it may slightly reduce the chance of catching a cold or shorten its duration, while others find no benefit. Differences in echinacea species, plant parts, and preparations make results hard to compare. At best, any effect is small, so echinacea should not be relied on to prevent colds.

Can herbs treat the flu?

No herbal product reliably prevents or treats influenza. The proven tools against the flu are annual vaccination, which reduces the risk and severity of illness, and prescription antiviral drugs for certain patients. Herbs may offer mild symptom comfort at best, so people, especially those at high risk, should not rely on them in place of vaccination and medical care.

Are cold and flu herbal supplements safe?

Many are generally safe in normal amounts, but supplements are loosely regulated, so quality, dose, and purity vary widely, and some can interact with medications or cause side effects. Raw elderberry is toxic if not prepared properly, and high-dose garlic or zinc can cause problems. Check labels for species, dose, and third-party testing, and consult a clinician if you take other medicines.

References

1. Hawkins J, Baker C, Cherry L, Dunne E. Black elderberry (Sambucus nigra) supplementation effectively treats upper respiratory symptoms: A meta-analysis of randomized, controlled clinical trials. Complementary Therapies in Medicine. 2019;42:361–365. PMID 30670267
2. Karsch-Völk M, Barrett B, Linde K. Echinacea for preventing and treating the common cold. JAMA. 2015;313(6):618–619. PMID 25668266
3. Hu XY, Wu RH, Logue M, et al. Andrographis paniculata for symptomatic relief of acute respiratory tract infections in adults and children: A systematic review and meta-analysis. PLOS ONE. 2017;12(8):e0181780. PMID 28783743
4. Lissiman E, Bhasale AL, Cohen M. Garlic for the common cold. Cochrane Database of Systematic Reviews. 2014;(11):CD006206. PMID 25386977
5. Oduwole O, Udoh EE, Oyo-Ita A, Meremikwu MM. Honey for acute cough in children. Cochrane Database of Systematic Reviews. 2018;4:CD007094. PMID 29633783
6. National Center for Complementary and Integrative Health. Flu and Colds: In Depth. nccih.nih.gov
7. National Center for Complementary and Integrative Health. European Elder. nccih.nih.gov
8. National Center for Complementary and Integrative Health. Echinacea. nccih.nih.gov
9. National Center for Complementary and Integrative Health. Garlic. nccih.nih.gov
10. National Center for Complementary and Integrative Health. Ginger. nccih.nih.gov

Last updated: October 1, 2026