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Safety

Does echinacea cause diarrhea?

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

It can, and it is among the most common side effects. NIH's Office of Dietary Supplements lists stomach upset, diarrhea, trouble sleeping and skin rashes, and a systematic review found that adverse events with echinacea are not commonly reported, with stomach upset and rashes the most frequent. Ask your doctor if diarrhea lasts or comes with other symptoms.1,2

Key facts

  • NIH's consumer sheet lists stomach upset, diarrhea, trouble sleeping and skin rashes as possible side effects of echinacea, and says allergic reactions occur in rare cases.1
  • NIH's health professional sheet says the most common of echinacea's few adverse effects are stomach and bowel upset such as diarrhea, sleeplessness and skin rashes.3
  • NCCIH says the most common side effects are digestive tract symptoms, such as abdominal pain, nausea or stomach pain.4
  • LactMed lists digestive upset, diarrhea, constipation and skin rash as reported effects, and says allergic reactions are rare.5
  • A 2014 Cochrane review of 24 trials with 4,631 participants found no significant difference between echinacea and placebo in dropouts or reported adverse effects.6

What do NIH, NCCIH and LactMed say about stomach effects?

The most common side effects are digestive: stomach upset, nausea, stomach pain and diarrhea.1,4

NIH's consumer fact sheet is the most direct: side effects can include stomach upset, diarrhea, trouble sleeping and skin rashes, and in rare cases allergic reactions. NCCIH names abdominal pain, nausea and stomach pain as the most common ones. LactMed lists gastrointestinal upset, diarrhea and constipation, along with skin rash.1,4,5

Trouble sleeping has been reported.1,3

How often does it happen in trials?

A 2005 systematic review drew on clinical studies and on reports to drug safety bodies. It concluded that adverse events with echinacea are not commonly reported, that stomach upset and rashes occur most often, and that short-term use has a relatively good safety profile with a slight risk of transient, reversible effects.2

The 2014 Cochrane review pooled 24 double-blind trials of echinacea products against placebo. Dropping out or reporting adverse effects did not differ significantly between the two groups, but in prevention trials there was a trend toward more dropouts due to adverse events with echinacea. The authors noted that the products varied by species, plant part and extraction.6

Neither review gave a rate for diarrhea on its own, so the sources tell us diarrhea happens, not how often.2,6

What about headaches, dizziness or other effects?

We found no official source that lists headaches, dizziness or heart palpitations as effects of echinacea. The effects the sources do list besides digestive upset are trouble sleeping, skin rashes and, rarely, allergic reactions, including severe ones. NIH adds isolated reports of raised liver enzymes and liver injury that may have come from a contaminant or the way a product was prepared.3,4

There are isolated reports of raised liver enzymes and liver injury linked to echinacea. NIH notes they may have been caused by a contaminant or the way the product was prepared.3,7

On blood thinning, the warfarin label names echinacea among botanicals that can interact with warfarin through liver enzymes. That is a drug interaction, not a blood-thinning effect of echinacea itself, and it has its own page.8

Who should ask their doctor about stomach upset and echinacea?

  • Anyone whose diarrhea lasts, or comes with blood, fever, vomiting or severe pain, should ask a doctor rather than put it down to echinacea.
  • Anyone with an allergy to daisy family plants such as ragweed, daisies or sunflowers should ask their doctor before using echinacea, because it belongs to that family.4
  • Anyone who takes warfarin or another blood thinner should ask their pharmacist, because the warfarin label names echinacea as a possible interaction.8
  • Anyone who takes medicines that suppress the immune system should ask their pharmacist, because NIH says echinacea might reduce their effectiveness.3
  • Anyone who plans to use echinacea for more than 10 days at a time should ask their doctor, because the European monograph limits pressed juice to 10 days.9

Questions people ask

Does echinacea cause diarrhea?

It can. NIH lists stomach upset and diarrhea among echinacea's possible side effects, and a systematic review found stomach upset and rashes the most frequent adverse events. Ask your doctor if it lasts.1,2

Does echinacea cause constipation?

LactMed lists constipation, along with digestive upset and diarrhea, among reported effects. NIH and NCCIH do not name it.1,5

Does echinacea cause headaches or dizziness?

We found no official source that lists headaches or dizziness. The sources list digestive upset, trouble sleeping, skin rashes and rare allergic reactions.3,4

Does echinacea cause blood thinning?

The warfarin label names echinacea among botanicals that can interact with warfarin through liver enzymes. That is an interaction, not blood thinning by echinacea. Ask your pharmacist if you take a blood thinner.8

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Sources

  1. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Immune Function and Infectious Diseases: Fact Sheet for Consumers. Updated March 10, 2025. Opened 2026-10-07.
  2. Huntley AL, Thompson Coon J, Ernst E. The safety of herbal medicinal products derived from Echinacea species: a systematic review. Drug Saf. 2005;28(5):387-400. Opened 2026-10-11.
  3. National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Immune Function and Infectious Diseases: Fact Sheet for Health Professionals. Updated March 10, 2025. Opened 2026-10-07.
  4. National Center for Complementary and Integrative Health. Echinacea. Bethesda (MD): National Institutes of Health. Last updated November 2024. Opened 2026-10-07.
  5. Drugs and Lactation Database (LactMed). Echinacea. Bethesda (MD): National Institute of Child Health and Human Development; 2006 onward. Entry revised October 15, 2024. Opened 2026-10-11.
  6. Karsch-Völk M, Barrett B, Kiefer D, Bauer R, Ardjomand-Woelkart K, Linde K. Echinacea for preventing and treating the common cold. Cochrane Database Syst Rev (a systematic review of randomized trials). 2014;2014(2):CD000530. Opened 2026-10-11.
  7. Echinacea. In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012 onward. Updated April 10, 2019. Summary read through PubMed. Opened 2026-10-07.
  8. Warfarin sodium tablets: prescribing information (Amneal Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published June 3, 2026. Opened 2026-10-07.
  9. European Medicines Agency, Committee on Herbal Medicinal Products. European Union herbal monograph on Echinacea purpurea (L.) Moench, herba recens. EMA/HMPC/48704/2014 Corr. 1. 24 November 2015. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.