For generations, echinacea has been a staple in Native American medicine, primarily used for treating colds, coughs, and respiratory infections, healing wounds and skin conditions like burns and insect bites, relieving pain from toothaches and sore throats, and supporting the body’s natural defence system. These traditional uses laid the foundation for echinacea’s reputation as a herb for immune support, and modern science has brought more clarity to this plant medicine’s specific effects, especially in reducing the incidence of colds and flu.
Today, it is widely associated with boosting immunity, but how does it actually work? Let’s break down the science-backed evidence.
At a glance
Extracts of the leaf, flower, and most commonly root of E. angustifolia and E. purpurea, can be found in dietary supplement products promoted to prevent and/or treat the common cold and other respiratory tract infections. Laboratory research strongly supports echinacea’s antiviral, antibacterial and immune-boosting actions, and clinical evidence supports it decreasing the incidence and duration of the common cold, though more research is required on the mechanism of action, and across different extracts.
The Plant
Echinacea species are perennials closely related to sunflowers and ragweed. Echinacea or purple coneflower, Echinacea purpurea, is a North American flowering plant (60cm/2ft), with lancet leaves and composite flowers with purple petals. The name derives from Greek echinos – hedgehog, on account of the appearance of and orange-yellow prickly seed cores. Roots are short and fibrous and are used medicinally.
Scientific Evidence on Immunity Support
Echinacea’s modern appeal comes from its potential to boost immune function, particularly in preventing and managing colds and respiratory infections. Scientific studies have provided more concrete insight into how it works.
Clinical studies support its use in the prevention of upper respiratory infections, reducing both the risk and duration of colds in some studies. In a meta-analysis of studies echinacea decreased the odds of developing the common cold by 58%, and the duration of a cold by 1.4 days. Echinacea is shown clinically to reduce antibiotic use in children through prevention of respiratory tract infection, and to be an expectorant and promote immune function. Disparities in the type of extract used means that some studies often show positive (if non-significant) trends, and the understanding of exactly how echinacea works (including its bioavailability and synergistic effects of the active compounds) to improve immune function requires further study.
There is also clinical evidence to show echinacea improves running economy (reducing the energy required to run), relieves eczema, and reduces anxiety.
How Echinaca Works: A Closer Look at the Mechanisms
Laboratory studies show echinacea boosts immune function, lowers inflammation and oxidation, and is antiviral and antibacterial. Echinacea also has analgesic actions, and cannabinoid activity, reducing anxiety. All these bioactivities are due to the combined chemicals in echinacea, rather than the individual chemical compounds that characterise the extracts.
Activation of immune cells. Research indicates echinacea stimulates the production of several different immune cells like neutrophils, fibroblasts, macrophages (white blood cells that surround and kill microorganisms, and stimulate the action of other immune cells) and natural killer cells, which are critical in fighting off infections. By enhancing the activity of these cells, echinacea can improve the body’s ability to defend itself against pathogens.
Reduction of inflammation. Echinacea extracts contain phenolic compounds and alkamides, both of which have direct anti-inflammatory properties that reduce the severity of symptoms in viral infections like the common cold by managing the body’s inflammatory response.
Modulation of cytokine activity. Crucially, regardless of the bacteria or virus that is causing the infection, echinacea has been found to regulate the release of cytokines, which are signalling proteins that help direct immune responses.
Data suggests that echinacea may lower pro-inflammatory cytokines (IL-6, IL-8, and TNF), as well as increase the anti-inflammatory cytokine (IL-10) and the proinflammatory cytokine IFM, which is reported to be low in patients with COVID-19. By keeping cytokine levels balanced, echinacea helps ensure that the immune system responds effectively without overreacting, which can lead to excess inflammation and associated damage.
Antiviral, antibacterial and antifungal properties. Laboratory studies indicate that echinacea shows potent and selective antibacterial, antiviral and antifungal properties. In laboratory studies, echinacea has action against various fungi, including Sacchromyces cerevisiae and various Candida species; against various bacteria including Staphylococcus aureus, Legionella pneumophila and E. coli; and against various viruses including herpes simplex 1+2, influenza A2, Hemophilus influenzae (associated with otitis media, chronic bronchitis and pneumonia), and several coronaviruses including SARS-CoV-2.
Active Chemicals in Echinacea
Echinacea roots, flowers and leaves contain polysaccharides, alkamides such as isobuylamides, phenolic acids such as caffeic acid, flavonoids, and an essential oil:
Alkamides have been shown to enhance the activity of immune cells and modulate inflammation. They play a role in stimulating macrophages and other immune cells.
Polysaccharides support immune function by promoting the activity of immune cells and enhancing their response to pathogens.
Flavonoids such as quercetin, kaempferol, and rutin possess antioxidant and anti-inflammatory properties. They help protect cells from damage and support immune function.
Caffeic acid and chicoric acid have antioxidant and immune-modulating effects. They contribute to reducing oxidative stress and inflammation.
Essential oil from echinacea, containing eugenol and caryophyllene, has antimicrobial and anti-inflammatory effects, aiding in the fight against infections and reducing inflammation.
Glycoproteins in echinacea are involved in modulating immune responses by influencing immune cell activation and proliferation.
How to Take Echinacea
Traditionally its the root that is used to make capsules, tinctures, decoctions (simmered tea) and teas, though the leaves and flowers are also active and are now often used. Echinacea is taken by many people during the winter months to support the immune system. Always read the label for the correct dose and caution.
Safety Not taken on an empty stomach. May interfere with immunosuppressant drugs. Orally, echinacea is well-tolerated with studies showing no difference when comparing echinacea to a placebo control. Side-effects in certain individuals can include abdominal pain, constipation, diarrhea, heartburn, nausea and vomiting, rashes and stomach upset. Severe allergic reactions and hepatitis have been reported. There is no known tolerable upper limit for echinacea, and doses vary widely across commercial products and various extracts.
As always: consult with a NIMH medical herbalist or your healthcare provider before starting any new plant medicine if you are pregnant, giving it to a child, have any allergies, medical condition/s or are taking any medication.
Conclusion: Tradition Meets Science
While echinacea’s traditional use as a healing plant medicine is well-documented and modern science is increasingly backing its reputation for supporting immunity, more research is required to determine its exact mechanisms of actions and which active extracts to use. With research pointing to its ability to activate immune cells, reduce inflammation and oxidation, and help fight infections, echinacea is proving to be a valuable science-based immunostimulant.
For those looking to naturally enhance their immune defences, echinacea offers a scientifically supported option.
