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Quick answer
Echinacea, also called purple coneflower, is one of the best-known herbal remedies for colds. It has been studied a lot, but the results are disappointing for most people.
- For treating a cold: a large Cochrane review found that echinacea products have not been shown to shorten or ease colds in a clear, reliable way.
- For preventing colds: the same review found a small trend towards fewer colds, but the result was not statistically certain. The US National Center for Complementary and Integrative Health (NCCIH) says echinacea may slightly lower the chance of catching a cold.
- Safety: short-term use of Echinacea purpurea products is likely safe for most adults, but allergic reactions happen and can occasionally be severe.
- Bottom line: if you want to try it, expect a small effect at best. Rest, fluids and simple self-care remain the main way to get through a cold.
What the research says
Echinacea is a group of flowering plants native to eastern North America, related to daisies, sunflowers and ragweed. Three species are used in supplements: Echinacea purpurea, E. angustifolia and E. pallida. Products are made from different parts of the plant (flowers, leaves, roots or pressed juice) and in different ways, which is one reason studies disagree.
The Cochrane review. The most thorough summary is a Cochrane systematic review published in 2014. It pooled 24 double-blind randomised trials with 4,631 participants, comparing a range of echinacea products with placebo.
- Prevention: ten trials tested whether taking echinacea regularly stopped people catching colds. None of the individual comparisons showed a clear, statistically significant difference. When the authors combined results in an extra analysis, they saw a possible 10% to 20% relative reduction in the risk of a cold, but they stressed that this was not a statistically significant finding.
- Treatment: fifteen trials tested echinacea taken once symptoms started. Six of these reported how long colds lasted, and only two of those six found a meaningful benefit over placebo.
- Conclusion: the authors concluded that echinacea products have not been shown to help treat colds. They thought a weak benefit from some products was possible, because prevention trials kept leaning in a positive direction, but questioned whether such a small effect matters in everyday life.
NCCIH's view. NCCIH's fact sheet, updated in 2024, gives a similar picture. It says echinacea may slightly reduce the chance of catching a cold, and that it is still unclear whether it shortens a cold. It notes one study suggesting echinacea might reduce respiratory infections in children, but says the evidence is not strong enough to show a clear link.
The NHS view. The NHS common cold page says there is little evidence that supplements such as echinacea, vitamin C or garlic prevent colds or help you recover faster.
European regulators. The European Medicines Agency (EMA) has assessed one specific type of product: juice pressed from the fresh flowering tops of Echinacea purpurea. It accepts this for the short-term prevention and treatment of colds in adults and young people over 12, based on long use in Europe and adult trials in which it was taken at the start of symptoms. This applies only to that kind of preparation, not to every echinacea product on the shelf.
Why the results vary. Because studies used different species, plant parts, extraction methods and doses, the Cochrane authors said it was difficult to draw strong conclusions about echinacea as a whole. A good result for one product does not prove that a different product works.
How people use it
There is no single proven dose, because the products studied vary so much. If you decide to try echinacea:
- Read the label. Look for the species and plant part used. The type assessed by the EMA is pressed juice or dried juice from the flowering parts of Echinacea purpurea. Follow the dose on the pack and do not take more than stated.
- Start early. In the trials the EMA relied on, people started taking it at the first signs of a cold.
- Keep it short. Echinacea is meant for short-term use. The EMA advises talking to a doctor or pharmacist if cold symptoms last more than 10 days.
- Choose a reputable brand. In the US, supplements are not approved by the FDA before they are sold, and the manufacturer is responsible for quality and labelling.
- Do not rely on it alone. Rest, drinking enough fluids and simple measures such as steam for a blocked nose or a salt water gargle for a sore throat are still the core of cold care.
Possible side effects and interactions
For most adults, short-term use appears to be well tolerated. In the Cochrane review, side effects and dropouts were broadly similar to placebo, although prevention trials showed a trend towards more people stopping echinacea because of side effects.
Reported side effects include:
- Digestive upset: NCCIH says stomach pain and nausea are the most common side effects.
- Allergic reactions: rashes are the most common sign. The EMA notes that serious reactions, including anaphylaxis, asthma attacks and a severe skin reaction called Stevens-Johnson syndrome, have been reported, mostly in people prone to allergies.
- Other effects: Memorial Sloan Kettering Cancer Center lists headache, dizziness and constipation among possible side effects.
Interactions. NCCIH says evidence is conflicting on whether echinacea affects medicines broken down by the liver, and there are theoretical concerns with immunosuppressant drugs and caffeine. Memorial Sloan Kettering advises caution because echinacea may make immunosuppressants such as tacrolimus or ciclosporin less effective, and it may interact with some cancer treatments. If you take any regular medicine, check with a pharmacist before using echinacea.
Who should avoid it
Talk to a doctor or pharmacist first, or avoid echinacea, if you:
- Are allergic to plants in the daisy family, such as ragweed, daisies or sunflowers. The EMA lists an allergy to this plant family (Asteraceae) as a reason not to use it.
- Have asthma, eczema or other allergies, because serious allergic reactions have mostly been reported in allergy-prone people.
- Take immunosuppressants, for example after an organ transplant or for an autoimmune condition, or are having chemotherapy.
- Are pregnant or breastfeeding. NCCIH says some extracts are possibly safe for up to 7 days in early pregnancy, but little is known about breastfeeding, so ask a professional first.
- Want to give it to a child. In one trial, some children taking echinacea developed rashes that may have been allergic. NCCIH advises checking with a child's doctor, and the EMA does not support use under 12.
When to see a doctor
Most colds clear up within one to two weeks. The NHS advises seeing a GP if:
- you have a high temperature that lasts more than 3 days, or a very high temperature with shivering
- your symptoms get worse, or have not improved after 10 days
- you feel short of breath or have chest pain
- a cough lasts more than 3 weeks
- you have a long-term condition such as diabetes, or a heart, lung or kidney condition
- you have a weakened immune system, for example during chemotherapy
- you are worried about a child's symptoms
Get emergency help straight away for severe breathing difficulty or signs of a serious allergic reaction.
Frequently asked questions
Does echinacea shorten a cold?
Probably not by much, if at all. In the Cochrane review, only two of six treatment trials that measured cold length found a benefit, and the authors concluded echinacea has not been shown to help treat colds.
Can I take echinacea every day to avoid colds?
Long-term daily use is not well supported. Prevention trials showed only a small, uncertain trend towards fewer colds, and products are intended for short courses.
Is echinacea tea as good as capsules or drops?
There is no good evidence either way. Products differ in species, plant part and strength, so a result from one product cannot be assumed for another. The preparation assessed by the EMA is a pressed juice taken by mouth, not a tea.
Can I take echinacea with zinc or vitamin C?
None of the three has strong evidence for treating a cold. The NHS says there is little evidence that supplements like these help you recover faster, and combination products make it harder to know what dose you are getting. Check with a pharmacist if you take other medicines.