Echinacea
Echinacea species are perennials closely related to sunflowers, daisies, and ragweed. Taking echinacea may slightly reduce your chances of catching a cold, but studies are mixed and it's unclear whether it can shorten a cold.
Echinacea species are perennials that are closely related to sunflowers, daisies, and ragweed.
Where to get it
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Traditional & historical use
Echinacea species were used by many North American Indigenous peoples to treat wounds, infections and toothaches long before European contact. It was adopted into American folk medicine in the 19th century and became widely used in Europe in the 20th century as an immune-support remedy.
Active compounds & mechanisms
Key compounds: alkylamides, polysaccharides, caffeic acid derivatives (echinacoside, cichoric acid), glycoproteins
Echinacea acts through multiple immune-modulating pathways. Alkylamides bind to cannabinoid receptors (CB2) and modulate cytokine production. Polysaccharides activate macrophages. Caffeic acid derivatives have antioxidant properties. Together these compounds appear to prime the innate immune system, which may explain why echinacea is associated with shorter duration — rather than prevention — of colds in some trials. Species and preparation matter: E. purpurea aerial parts are the most studied.
Research & evidence
Strong support Some support Weak or no supportColours show how well the sources back each point. The reason is next to each one.
NCCIH says taking echinacea may slightly reduce your chances of catching a cold. MSK says clinical data indicate that echinacea is ineffective in preventing the common cold caused by rhinoviruses, and that other analyses show weak evidence for a prophylactic benefit.
Mixed evidenceSome support. Results are mixed
Study details
NCCIH (What Have We Learned?): "Taking echinacea may slightly reduce your chances of catching a cold." | MSK (Research Findings (Clinical Summary)): "Clinical data indicate that echinacea is ineffective in preventing the common cold caused by rhinoviruses" | MSK (Research Findings (Clinical Summary)): "Other analyses do not indicate any benefits for treating colds, and weak evidence for a prophylactic benefit"
Source: NCCIH, Echinacea (Last Updated November 2024), What Have We Learned? View source
NCCIH says it's still unclear whether echinacea can shorten the length of a cold. MSK says studies of its ability to reduce incidence and duration of the common cold yielded mixed results.
Mixed evidenceSome support. Results are mixed
Study details
NCCIH (What Have We Learned?): "It's still unclear whether echinacea can shorten the length of a cold." | MSK (Research Findings (Clinical Summary)): "Studies of its ability to reduce incidence and duration of the common cold yielded mixed results"
Source: NCCIH, Echinacea (Last Updated November 2024), What Have We Learned? View source
NCCIH says one recent study found that echinacea might reduce the chance of respiratory tract infection, but overall there isn't enough evidence to support a clear connection.
Limited evidenceSome support. Reviewers rated the certainty low
Study details
NCCIH (What Have We Learned?): "One recent study found that echinacea might reduce the chance of respiratory tract infection" | NCCIH (What Have We Learned?): "but overall, there isn't enough evidence to support a clear connection."
Source: NCCIH, Echinacea (Last Updated November 2024), What Have We Learned? View source
NCCIH says it's unclear whether echinacea is helpful for other health conditions, including eczema.
Limited evidenceSome support. Reviewers rated the certainty low
Study details
NCCIH (What Have We Learned?): "It's unclear whether echinacea is helpful for other health conditions, including eczema."
Source: NCCIH, Echinacea (Last Updated November 2024), What Have We Learned? View source
Dosage
| Form | Amount |
|---|---|
| Capsule | 300–500 mg of E. purpurea extract (standardised), up to 3× per day at first sign of illness for up to 10 days |
| Tincture | 1–4 mL (20–40 drops) of E. purpurea tincture up to 3× per day for up to 10 days during acute illness |
Side effects
The most common side effects of echinacea are digestive symptoms such as abdominal pain, nausea and stomach pain. Some people have allergic reactions, which may be severe. MSK says people with allergies or asthma and people having chemotherapy should use caution. If you take any medicine, talk to your health care provider before using echinacea.
Well documented Reported (case reports, anecdotal or one study) None reportedThe circle shows how well documented an effect is, not how serious it is. A rarely reported effect can still be serious, so always read ‘When to stop’.
| Effect | Frequency | When to stop |
|---|---|---|
| Abdominal pain, nausea, stomach pain (digestive tract symptoms)Well documentedListed plainly by NIH, MSK or LiverTox | Described as the most common side effects | Stop and talk to a doctor if you notice any unexpected or concerning symptoms. |
| Allergic reactions, which may be severeWell documentedListed plainly by NIH, MSK or LiverTox | Not stated | Stop and talk to a doctor if you notice any unexpected or concerning symptoms. |
| Rashes in children (seen in a clinical trial)ReportedCase reports only | Not stated | Stop and talk to a doctor if you notice any unexpected or concerning symptoms. |
Safety & interactions
Safety
NCCIH says it's likely safe for most adults to consume products with extracts of E. purpurea, and possibly safe for children to consume E. purpurea extract for short periods of time. The most common side effects of echinacea are digestive tract symptoms, such as abdominal pain, nausea, or stomach pain. However, some people have allergic reactions to echinacea, which may be severe. NCCIH says there is conflicting evidence about whether echinacea interacts with some drugs. If you take any type of medicine, talk to your health care provider before using echinacea.
Contraindications
NCCIH says there is concern that allergic reactions could be severe in some children, and that some children participating in a clinical trial of echinacea developed rashes. MSK says patients with allergies or asthma should exercise caution with echinacea, as allergic reactions have been reported, and that patients undergoing chemotherapy should use caution with echinacea. NCCIH says the information it has suggests echinacea is possibly safe for up to 7 days during the first trimester of pregnancy, and that if you're considering using echinacea while pregnant you should consult your health care provider. NCCIH says little is known about whether it's safe to use echinacea while breastfeeding. MSK says to talk to your healthcare provider before taking echinacea in any form if you're pregnant or breastfeeding.
Drug interactions
NCCIH says there are theoretical reasons to suspect that echinacea might interact with immunosuppressants. MSK says echinacea may antagonize the effects of immunosuppressants.
NCCIH says there are theoretical reasons to suspect that echinacea might interact with caffeine.
MSK reports that echinacea caused profound thrombocytopenia (a low platelet count) in a patient receiving etoposide, likely due to the inhibition of CYP3A4. MSK says patients undergoing chemotherapy should use caution with echinacea.
MSK says echinacea inhibits CYP3A4 and CYP2C8 and can affect the intracellular concentration of drugs metabolized by this enzyme. MSK says caution should be used when echinacea is coadministered with drugs dependent on CYP3A or CYP1A2 for their elimination.
Established: stated plainly by an authoritative source. Documented: supported by case reports or trial data. Theoretical: based on mechanism, animal data, or a cautious listing. Always check with your pharmacist or prescriber.
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