Europe's 2009 dandelion monograph lists 7 situations in which the root should not be used, including gallstones and liver disease. Most product pages sell it for the liver without mentioning the second.
Side effects in people are mostly mild and uncommon, so this page spends its time on the situations where dandelion root is the wrong choice, and names the source for each.
Quick Answer: What Are Dandelion Root's Side Effects?
Europe's 2009 monograph lists stomach pain, excess acidity and allergic reactions. The bigger issue is who should avoid it: people allergic to ragweed and other daisy-family plants, anyone with gallstones, bile duct problems or liver disease, and people on lithium, diuretics or potassium-raising drugs. Safety in pregnancy is not established.
Key Takeaways
- Europe's 2009 monograph lists stomach pain, acidity and allergy as side effects.
- It rules out gallstones, bile duct blockage, liver disease and 4 more.
- In 1 study, 18 of 20 daisy-allergic patients reacted to Asteraceae teas.
- PubMed holds 0 dandelion-lithium studies; the caution comes from lithium's label.
- Europe flags kidney failure, diabetes and heart failure: 3 potassium risks.
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Side Effects Reported in People
Dandelion is a common food, and the side effects reported for the root are mostly mild. Europe's 2009 monograph lists stomach pain, excess acidity and allergic reactions, each with unknown frequency.[1]Dandelion Root with Herb, Traditional Use Monograph — European Medicines Agency View source MSKCC adds heartburn, and mild diarrhea with high doses.
- Stomach: pain and excess acidity, frequency unknown.
- Allergy: rash or breathing symptoms in people sensitive to the daisy family.
- Low blood sugar: reported, mainly a concern alongside diabetes medicine.
- Long-term use: no study has followed daily use for months.
For the plant and the size of its research record, see what dandelion root is and how little of it was tested in people.
Ragweed and the Daisy Family
Dandelion belongs to the Asteraceae, the family that includes ragweed, chamomile, chrysanthemums, marigolds and daisies. People allergic to 1 of them can react to others, and the evidence comes from skin-prick and patch tests rather than from dandelion trials.
| Study | Who was tested | What it found |
|---|---|---|
| 1943[2]Allergenic relationship of the pollens of dwarf and giant ragweed to several of their botanic relatives — Journal of Experimental Medicine (1943) View source | 40 ragweed-allergic patients | 38 also reacted to pollen of related plants |
| 2006[3]Contact allergy to herbal teas derived from Asteraceae plants — Contact Dermatitis (2006) View source | 20 patients allergic to daisy-family compounds | 18 reacted to Asteraceae teas, mainly chamomile, dandelion and wormwood |
| 2007[4]Cross-allergenicity of pollens from the Compositae family: Artemisia vulgaris, Dendranthema grandiflorum, and Taraxacum officinale — Annals of Allergy, Asthma and Immunology (2007) View source | 6,497 allergy patients, skin-prick tested | 8.5% sensitized to dandelion pollen; mugwort blocked up to 86% of that reaction |
Those 3 studies span 64 years. The US NCCIH calls the evidence on ragweed cross-reaction conflicting, which is a reason for caution rather than certainty.[5]Dandelion: Usefulness and Safety — National Center for Complementary and Integrative Health View source
Gallstones, Bile Ducts and Liver Disease
Europe's monograph rules dandelion root out in 7 situations, and most involve the bile system. It gives no reasons, but the root's traditional use as a bitter that promotes bile flow is the likely link, and it is why these are firm stops rather than cautions.
- Allergy to dandelion or any Asteraceae plant.
- Blocked bile ducts.
- Cholangitis, an inflamed bile duct.
- Liver disease.
- Gallstones.
- Active peptic ulcer.
- Any other disease of the bile system.
Liver disease on that list surprises people who buy the root for the liver. The animal evidence behind the bile-flow claim is real, and it is no substitute for a hepatologist.
Lithium, Diuretics and Potassium
These cautions come from what dandelion is believed to do rather than from documented cases. PubMed holds 0 studies of dandelion with lithium, but if the plant acts as a diuretic, the rules that apply to water pills apply to it too.
| Medicine | Why it matters | Source of the caution |
|---|---|---|
| Lithium | Diuretics can reduce lithium clearance and raise blood levels | Lithium prescribing label |
| Prescription diuretics | Effects could add up | NCCIH, MSKCC |
| Potassium supplements or potassium-raising drugs | The leaf is potassium-rich; Europe flags high potassium | EMA monograph |
| Diabetes medicines | Low blood sugar has been reported | MSKCC, 2010 case report |
| Anticoagulants and antiplatelets | Theoretical interaction | NCCIH |
Lithium labels tell prescribers to check levels more often when a diuretic is added.[6]Lithium Carbonate Prescribing Information, Drug Interactions — DailyMed, National Library of Medicine View source Ask your pharmacist whether any of your medicines raise potassium.
Kidneys and Blood Sugar
Dandelion is sold for kidney health on many websites. A 2014 nephrology review found it among the 10 plants most promoted online for kidney disease, without adequate human study behind any of them.[7]Internet claims on dietary and herbal supplements in advanced nephropathy: truth or myth — American Journal of Nephrology (2014) View source
- Kidney failure: Europe advises avoiding it because of possible high potassium.
- Heavy tea use: a 2013 finger necrosis case involved a man with kidney disease drinking 10 to 15 cups a day.[8]Dandelion, About Herbs — Memorial Sloan Kettering Cancer Center View source
- Diabetes: 1 of Europe's 3 potassium-risk conditions, and low blood sugar has been reported.[9]First report of hypoglycemia secondary to dandelion (Taraxacum officinale) ingestion — American Journal of Emergency Medicine (2010) View source
- Kidney stones: lab and rat data only.
If a daily cup of the tea is your habit, the same cautions apply to it.
Pregnancy, Children and Fertility
There are no human data on dandelion root in pregnancy. Europe's monograph does not recommend it during pregnancy or breastfeeding, and does not recommend it for children under 12 because adequate data are lacking.
- Pregnancy: not recommended, safety not established.
- Breastfeeding: not recommended.
- Under 12: not recommended.
- Male fertility: a 2011 rat study found lower sperm counts after 60 days.[10]Dandelion (Taraxacum officinale) decreases male rat fertility in vivo — Journal of Ethnopharmacology (2011) View source
Other Products That Already Contain Dandelion
Dandelion root turns up in many liver, detox and kidney blends, including some of ours. Taking a single-herb capsule on top of a blend raises the dose without you noticing.
- Liver Safeguard: contains dandelion root.
- Go-Stone: contains dandelion root.
- Ultimate Detox capsules and tea: contain roasted dandelion root.
- Liver Health Power Pack: lists dandelion root among its ingredients.
A 2022 case report described liver injury in a 36-year-old woman after a liver detox tea combining dandelion root, burdock, nettle and other herbs.[11]Drug-Induced Liver Injury from Herbal Liver Detoxification Tea — Case Reports in Gastroenterology (2022) View source
How to Use It Safely
For a healthy adult who is not pregnant, has no daisy-family allergy and no gallbladder or liver disease, and takes none of the medicines above, dandelion root has a reassuring record as a food. These habits cover most of the practical risk.
- 1 source: not a capsule plus a blend plus daily tea.
- Tell your prescriber: if you take any regular medicine.
- Review at 2 weeks: Europe's point for seeing a doctor if symptoms persist.
- Stop: with a rash, wheezing, stomach pain or shakiness.
Kept to 1 source, dandelion root in a measured capsule makes your total easy to know.
Stop or Speak to a Clinician First If
- You are allergic to ragweed, chamomile, marigolds, daisies or another daisy-family plant
- You have gallstones, a blocked bile duct, cholangitis or liver disease
- You take lithium, a prescription diuretic, or a medicine that raises potassium
- You have kidney failure, heart failure or diabetes, where Europe flags a potassium risk
- You are pregnant or breastfeeding, where safety has not been established
Frequently Asked Questions
Who should avoid taking dandelion root? +
People allergic to daisy-family plants, anyone with gallstones, bile duct disease, liver disease or an active peptic ulcer, and anyone pregnant or breastfeeding. Europe's 2009 monograph lists these.
What not to mix with dandelion root? +
Lithium, prescription diuretics, potassium-raising drugs and diabetes medicines, plus blood thinners as a theoretical risk. A 1999 rat study also found it cut peak ciprofloxacin levels by 73%.
Is dandelion root hard on your kidneys? +
There is no evidence it harms healthy kidneys, but Europe's 2009 monograph says people with kidney failure should avoid it because of a risk of high potassium.
Are there any negative side effects of dandelion root? +
Yes, uncommon ones: stomach pain, excess acidity and allergic reactions, according to Europe's 2009 monograph. Low blood sugar has also been reported.
What is the downside of dandelions? +
For supplements, the main downside is thin evidence: 1 trial of dandelion alone in people, and it used the leaf. The other is the allergy and medicine cautions on this page.
Who should not drink dandelion root tea? +
The same people who should avoid the capsule: anyone with a daisy-family allergy, gallstones, bile duct or liver disease, or on lithium or diuretics. Europe's 2009 monograph also advises against it in pregnancy.
Can dandelion root cause an allergic reaction? +
Yes. In a 2006 patch-test study, 18 of 20 people allergic to daisy-family compounds reacted to Asteraceae teas, mainly chamomile, dandelion and wormwood.
Is dandelion root safe during pregnancy? +
It is not recommended. Europe's 2009 monograph says safety in pregnancy and breastfeeding has not been established, and there are 0 human trials.
Can I take dandelion root with blood thinners? +
Ask first. The US NCCIH lists anticoagulant and antiplatelet drugs among theoretical interactions, and 0 trials have tested the combination.
Should I stop dandelion root before surgery? +
There is no specific evidence, but stopping herbs 2 weeks before planned surgery is a common precaution, especially with blood thinners or diabetes medicine. Follow your surgical team.
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