Dandelion

What it is

Dandelion is a flowering plant in the Asteraceae (daisy) family that grows worldwide. Its roots, leaves and flowers are used in traditional medicine and eaten as tea or a vegetable. It contains triterpenes, phenolic acids, sterols, flavonoids and other plant compounds.

What the research says

Most of the evidence is from animal and cell studies. In people, the only single-herb trial we found was a one-day pilot in 17 volunteers: urination went up after two of three doses, with no placebo group. The European Medicines Agency's herbal committee (2021 draft) found no clinical trial data and accepted the root only as a traditional remedy, based on long-standing use rather than trials, for mild digestive complaints, temporary loss of appetite, and increasing urine flow as an add-on in minor urinary complaints. Harms include allergy in people sensitive to the daisy family, stomach complaints, a fatal case linked to very heavy tea drinking, and possible drug interactions.

Evidence grade: Not enough research to say.

What goes wrong

Dandelion can cause allergic contact dermatitis, and anaphylaxis is possible because of its sesquiterpene lactones; hypersensitivity to the Asteraceae family is a contraindication. (Source 1)

• Official position, Low certainty.
• Size: not applicable.
• Who: people sensitive to Asteraceae plants.
• How long: not applicable.
• Result: not quantified.
• Funding: regulator (EMA)

Anaphylaxis and pseudoallergic contact dermatitis is possible due sesquiterpene lactones

A case report describes a 56-year-old man who developed painful blackening of the fingertips after drinking 10 to 15 cups of dandelion tea a day for 6 months; he died 9 months after diagnosis. (Source 1)

• Case report, Very low certainty.
• Size: 1 patient.
• Who: 56-year-old man (chronic kidney disease per MSKCC)
• How long: 6 months of heavy tea intake.
• Result: digital necrosis linked to secondary hyperoxalaemia; death 9 months after diagnosis.
• Funding: not stated.

had been drinking 10–15 cups of dandelion tea (no plant part known) daily for 6 months

Case reports link dandelion-containing products to acute liver injury (a detox tea) and to toxic blood levels of transplant anti-rejection drugs (a tea), with dandelion tea extract inhibiting CYP3A4 in vitro. (Source 2)

• Case report, Very low certainty.
• Size: single cases.
• Who: a 36-year-old woman; a kidney transplant recipient.
• How long: not stated.
• Result: liver injury resolved after stopping; toxic immunosuppressant levels.
• Funding: not stated.

In vitro, dandelion tea extract inhibited CYP3A4, which is used in the metabolism of these drugs.

Dandelion may add to the effects of diuretic and blood-sugar-lowering medicines, based mainly on animal and in-vitro studies. (Source 2)

• Official position, Very low certainty.
• Size: not applicable.
• Who: people on diuretics or diabetes medicines.
• How long: not applicable.
• Result: not quantified.
• Funding: not stated.

Diuretics: Animal and human studies suggest dandelion may have additive effects due to its diuretic activity.

Dandelion can accumulate heavy metals such as lead, cadmium and nickel from its environment, and in rats it altered how the antibiotic ciprofloxacin was handled. (Source 3)

• Systematic review, Very low certainty.
• Size: not applicable.
• Who: not applicable.
• How long: not applicable.
• Result: not quantified.
• Funding: not stated.

Environmental changes lead to the accumulation of heavy metals such as lead, cadmium (Cd) and nickel (Ni) in dandelion.

EMA's 2021 draft reports stomach upset (hyperacidity or gastric complaints) as an undesirable effect. (Source 1)

• Official position, Low certainty.
• Size: not applicable.
• Who: users.
• How long: not applicable.
• Result: frequency not stated.
• Funding: regulator (EMA)

A hyperacidity (Schulz et al. 2001) or gastric complaints (Capasso 2003) may occur.

What the evidence supports

In a one-day pilot study in 17 volunteers with no placebo group (each person compared with their own baseline), dandelion leaf extract significantly increased how often people urinated after the first dose, and the urine-to-fluid-intake ratio after the second dose; the third dose had no effect. (Source 4)

• Case series, Very low certainty.
• Size: 17 volunteers.
• Who: healthy volunteers.
• How long: 1 day of dosing plus 24 hours follow-up.
• Result: increased urination frequency after dose 1 (p<0.05); increased excretion ratio after dose 2 (p<0.001); no change after dose 3.
• Funding: not stated.

For the entire population (n = 17) there was a significant (p < 0.05) increase in the frequency of urination in the 5-hour period after the first dose.

What the evidence does not support

In the same pilot, the third dose did not change any measured outcome. (Source 4)

• Case series, Very low certainty.
• Size: 17 volunteers.
• Who: healthy volunteers.
• How long: 1 day.
• Result: no change.
• Funding: not stated.

The third dose failed to change any of the measured parameters.

The EMA herbal committee's 2021 draft assessment found no clinical efficacy data for dandelion root. (Source 1)

• Official position, Certainty not rated.
• Size: not applicable.
• Who: not applicable.
• How long: not applicable.
• Result: no clinical trials identified.
• Funding: regulator (EMA)

4.2.2. Clinical studies (case studies and clinical trials) No data available.

MSKCC notes that most reported dandelion activities come from test-tube and animal studies, and that clinical trials are still needed. (Source 2)

• Official position, Very low certainty.
• Size: not applicable.
• Who: not applicable.
• How long: not applicable.
• Result: not applicable.
• Funding: not stated.

Clinical trials are needed to determine the conditions under which dandelion may be safe and effective.

How much

• Reference intake: No RDA or AI exists for dandelion as such; it is a herb, not an essential nutrient. The EMA HMPC 2021 draft accepts the root only as a traditional herbal medicinal product (for mild digestive disorders, temporary loss of appetite, and increasing urine flow as an adjuvant in minor urinary complaints). (Source 1)
• Upper limit: No tolerable upper intake level has been set in the sources we reached. (Source 1)
• Studied: 8 mL of fresh-leaf hydroethanolic extract three times in one day (Clare 2009 pilot). (Source 4)

A common belief, and what the research shows

The belief: Dandelion is a proven liver detox and diuretic.

What the research shows: The EMA herbal committee found "4.2.2. Clinical studies (case studies and clinical trials) No data available." for the root, and the only single-herb human diuretic study was a 17-person, one-day pilot. MSKCC lists a case of "Acute liver injury: In a 36-year-old woman after drinking an herbal liver detox tea containing dandelion."

Questions and answers

What is it?

Dandelion is a common yellow-flowered plant in the daisy family. Its roots, leaves and flowers are used in traditional medicine and are eaten as a vegetable or drunk as tea. (Source 3)

What does it do in the body?

Most reported effects (antioxidant, anti-inflammatory, liver-protective, diuretic) come from lab and animal work. One small, uncontrolled human study found more urination after dandelion leaf extract over a single day. (Source 2)

Is it good or bad for you?

As food it is widely eaten, but as a remedy its benefits are unproven in people. It can cause allergy in people sensitive to daisy-family plants. Very heavy tea drinking was linked to a fatal case, and it may interact with some medicines. (Source 2)

How do you get more of it?

It is eaten as leaves (greens), drunk as tea, or taken as root or leaf extracts. The one human study gave 8 mL of leaf extract three times in a day. (Source 4)

If it is harmful, what reduces it?

Does not apply as a body level. People allergic to daisy-family plants are advised against it by the EMA committee, and in case reports symptoms eased after the product was stopped. (Source 1)

Why might someone be low in it or missing it?

Does not apply. Dandelion is not an essential nutrient, so there is no deficiency state to be low in. (Source 1)

We searched: EMA HMPC 2021 draft assessment, Yan 2024 review, MSKCC monograph; none describe a deficiency.

Which whole foods contain it or feed it?

The plant itself is the food: the leaves are eaten as a vegetable and the plant is drunk as tea. Plants grown in polluted ground can take up heavy metals. (Source 3)

What happens if you do not have it?

Nothing is known to happen. Dandelion is not essential, and no deficiency effects are described. (Source 1)

We searched: EMA HMPC 2021; Yan 2024 review; MSKCC monograph.

How can you test for it?

We found no clinical test for dandelion intake or status in the literature we searched. (Source 3)

We searched: EMA HMPC 2021; Yan 2024 review; Clare 2009 pilot.

References

1. European Medicines Agency, Committee on Herbal Medicinal Products (copy hosted at fitoterapia.net). Assessment report on Taraxacum officinale F.H. Wigg., radix (draft, first version), EMA/HMPC/475725/2020, dated 05 May 2021. 2021. Read the source
2. Memorial Sloan Kettering Cancer Center. Dandelion (About Herbs), last updated February 8, 2023. 2023. Read the source
3. Biomedicine & Pharmacotherapy. The phytochemical and pharmacological profile of dandelion. 2024. Read the source
4. Journal of Alternative and Complementary Medicine. The Diuretic Effect in Human Subjects of an Extract of Taraxacum officinale Folium over a Single Day. 2009. PMID 19678785, DOI 10.1089/acm.2008.0152. Read the source