Echinacea: Benefits, Dosage, and Safety

What echinacea is

Echinacea is a genus of flowering plants (purple coneflower) native to areas east of the Rocky Mountains in the United States and closely related to sunflowers, daisies, and ragweed. Three species are most commonly used in supplements: Echinacea purpurea, Echinacea angustifolia, and Echinacea pallida. Products on the U.S. market often combine extracts from multiple species and plant parts (root, leaf, flower). It is not a nutrient and has no established dietary requirement; it is a botanical promoted mainly for immune support and respiratory infections, and sometimes applied topically for skin problems.

What it does

• Echinacea is a botanical, not an essential nutrient, so it has no required role in normal human physiology and no dietary requirement
• Laboratory research suggests echinacea may have antioxidant and antibacterial activity and may stimulate monocytes and natural killer cells (per ODS, based largely on in vitro data)
• May inhibit some viruses from binding to host cells in laboratory studies (ODS)
• May reduce inflammation in laboratory studies by inhibiting inflammatory cytokines such as interleukin-6, interleukin-8, and tumor necrosis factor and increasing the anti-inflammatory cytokine interleukin-10 (ODS)
• Historically used by Native Americans for respiratory tract infections, tooth pain, and snakebite, and in traditional medicine to promote wound healing

Intake and dosing

Echinacea is not an essential nutrient, so no Recommended Dietary Allowance or Tolerable Upper Intake Level has been set. Doses in studies vary widely. Because supplement doses are not standardised, discuss an appropriate amount with a clinician or pharmacist.

Deficiency and who is at risk

Echinacea is a botanical, not an essential nutrient, so there is no deficiency state and no NIH Dietary Reference Intake. No sign or symptom results from not consuming it.

Who may need more

• People are not required to consume echinacea; it is not an essential nutrient and no one needs it to meet a dietary requirement
• Some adults use short-term echinacea products in an attempt to reduce the chance of catching a cold, though NIH says any effect is slight and of uncertain clinical relevance
• People with allergies to plants in the daisy family (ragweed, marigolds, chrysanthemums) should be cautious because of allergic reaction risk
• Pregnant and breastfeeding people should consult a health care provider first; ODS reports experts recommend against use in pregnancy and little is known about breastfeeding
• Anyone taking prescription medication, especially immunosuppressants or drugs metabolized by the liver, should talk to a provider before use

Food sources

Echinacea is a medicinal herb, not a food nutrient, so it is not obtained from a normal diet. The plant material (root, leaf, flower of Echinacea purpurea, E. angustifolia, or E. pallida) is consumed only as prepared supplements, extracts, or herbal teas, not as a dietary food source.

Forms and absorption

Echinacea supplements are sold as capsules, tablets, liquid extracts and tinctures, expressed juice, and teas, and some products are formulated for topical use on the skin. Products vary widely in the echinacea species used (E. purpurea, E. angustifolia, E. pallida), the plant part (root, aerial parts, whole plant), and the extraction method, and many commercial products blend multiple species and parts. This variability is a major reason clinical trial results are inconsistent and hard to compare. There is no standardized or NIH-recommended dose; the amount of active constituents differs from product to product. Bioavailability of specific echinacea constituents has not been established by NIH.

Safety, excess and interactions

Too much

Echinacea appears to be safe and only a few adverse effects have been reported. According to NIH, the most common side effects are digestive tract symptoms such as abdominal pain, nausea, stomach pain, and diarrhea, along with sleeplessness and skin rashes. Because it is not an essential nutrient, there is no Tolerable Upper Intake Level. Isolated reports of elevated liver enzymes and liver injury have been associated with its use, but ODS notes these events could have been caused by a contaminant or the product's preparation rather than echinacea itself. In rare cases echinacea can cause allergic reactions, which may be severe.

Interactions to know

• Immunosuppressant medications: because echinacea may have immunostimulatory activity, ODS notes it might reduce the effectiveness of immunosuppressants; there are theoretical reasons to suspect an interaction (NCCIH)
• Drugs metabolized by the liver (cytochrome P450 enzymes): NCCIH reports conflicting evidence about whether echinacea interacts with some liver-metabolized drugs; ODS notes echinacea might increase cytochrome P450 activity and thereby reduce levels of some drugs metabolized by these enzymes
• Caffeine: NCCIH cites theoretical reasons to suspect echinacea might interact with caffeine
• General: NIH advises anyone taking any medication to talk with a health care provider before using echinacea, because some herbs and medicines interact in harmful ways

How status is measured

not routinely measured. There is no clinical laboratory marker for echinacea status because it is not an essential nutrient and the body has no requirement for it; NIH does not describe any test to measure echinacea intake or levels.

Echinacea is regulated as a dietary supplement, not a drug. Unlike drugs, dietary supplements are not approved by the U.S. Food and Drug Administration (FDA) before they are sold. Manufacturers and distributors are responsible for evaluating the safety and labeling of their products before marketing to ensure they meet regulatory requirements. The FDA can take action to protect the public when safety concerns arise about a supplement or ingredient. Echinacea is not FDA-approved to prevent, treat, or cure the common cold or any disease.

What the evidence supports

We grade the strength of evidence behind each common reason people take echinacea, mirroring how the NIH describes it.