Dandelion

The common dandelion grows from a stout, fleshy taproot, dark brown outside and white and milky within, that can reach a foot or more in good soil and divides at the crown with age (Grieve). Its leaves rise straight from the root in a rosette that lies close to the ground. They are hairless and cut into jagged, backward-pointing teeth, though Grieve notes that some forms are deeply lobed and others almost entire. Each flower stalk, or scape, is hollow, smooth, leafless, and unbranched and carries a single head about an inch and a half across (King’s American Dispensatory). What looks like one flower is a head of many strap-shaped, golden-yellow florets, each notched with five tiny teeth, set in a double ring of green bracts whose small outer scales spread or bend back (King’s). Grieve notes that heads open in the morning in fine weather and close in the evening and whenever rain threatens. After flowering the head closes again, then reopens as the familiar seed clock: a sphere nearly two inches wide of ribbed fruits, each lifted on a slender, thread-like beak with a parachute of soft white bristles that carries it on the wind (King’s). The whole plant bleeds a bitter white latex when cut, which Grieve notes stains the hands brown.

The name is less simple than the plant. Linnaeus called it Leontodon taraxacum in Species Plantarum (1753), and F.H. Wiggers published Taraxacum officinale in 1780, the name EMA’s herbal monographs still use. Kew’s Plants of the World Online now accepts the group as Taraxacum section Taraxacum and lists Taraxacum officinale among its 19 synonyms, while researchers often write Taraxacum officinale agg., for aggregate. The reason is apomixis: many common dandelions set seed without fertilization, so their offspring are essentially clones. In a review of dandelions and their relative skeleton weed (Chondrilla), van Dijk (Philosophical Transactions of the Royal Society B 2003) explains that apomictic dandelions are more widespread than sexual ones, that apomictic populations are highly polyclonal, and that new clones arise through rare crosses in which apomicts act as pollen donors to sexual plants. Some clones are geographically widespread, and van Dijk describes them as probably phenotypically plastic general-purpose genotypes: single genetic lines flexible enough to succeed in many different places. Chinese medicine mainly uses a related species, Taraxacum mongolicum, which MSKCC lists alongside T. officinale under the name pu gong ying.

The root and leaves carry several kinds of chemistry. EMA’s assessment reports list bitter sesquiterpene lactones such as taraxinic acid glucoside and 11β,13-dihydrolactucin; triterpenes and sterols including taraxasterol and β-sitosterol; phenolic acids led by chicoric and chlorogenic acids; and flavonoids such as luteolin glycosides. The root stores inulin, a fructose-based fiber, in amounts that EMA, citing Bisset, gives as about 2% in spring and up to 40% in autumn; King’s cites Dragendorff’s 1870 finding of 24% in October roots against 1.74% in March. The leaves are rich in potassium, with 30 to 48 mg per gram of dried leaf in one three-year study, against about 25 mg per gram (2.45%) in the root (EMA). The latex is chemically distinct: taraxinic acid glucoside makes up about 7% of latex from the main root (EMA, citing Huber 2015), and the same compound is a known skin sensitizer. Older pharmacists knew the chemistry changed with the seasons. King’s American Dispensatory records about 17% reducing sugar in roots dug in March, and Grieve explains that spring roots dry shriveled and porous while autumn roots, packed with inulin, dry firm.

Three parts are used medicinally: the dried root (Taraxaci radix), the leaf (Taraxaci folium), and the whole plant, root with herb (Taraxaci radix cum herba), each with its own EMA monograph. Products labeled only “dandelion” may contain any of them. The root has look-alikes. Chicory root, a close relative, was a common substitute; King’s and Grieve both note that it is paler, with its milk vessels in radiating lines rather than the concentric rings seen in a cut dandelion root, and Grieve records the hairy-leaved rough hawkbit (Leontodon hispidus) being passed off as dandelion. Grieve also observes that flowers easily mistaken for dandelion have either hairy leaves or branched flower stems, a useful check for foragers. Where the plant grows matters too. EMA’s assessment report cites surveys of wild dandelions that found lead at 0.5 to 45 mg/kg in plants from 29 US sites and up to 175 mg/kg at 13 Polish sites, along with cadmium and other metals. Plants from roadsides, industrial ground, or sprayed lawns are poor choices for the kitchen or the teapot.

According to Grieve’s A Modern Herbal (1931), dandelion first appears as a medicine in the works of Arabian physicians of the tenth and eleventh centuries, who described it as a kind of wild endive under the name taraxacon, and it turns up in Welsh medical texts of the thirteenth century. The English name is a corruption of the French dent de lion, lion’s tooth, echoed in the old Latin Dens leonis and in Linnaeus’s Greek genus name Leontodon. Grieve reports some doubt that the leaves were the true inspiration. She cites the Ortus Sanitatis of 1485, which credits a surgeon, Master Wilhelmus, with likening the herb to a lion’s tooth because of its virtues, and notes the yellow flowers and white root as other suggested origins. She derives Taraxacum from the Greek taraxos, disorder, and akos, remedy, while noting an alternative reading. Folk names are just as vivid. Grieve records priest’s crown, for the bare seed head, and swine’s snout, for the closed head after flowering; NCCIH adds lion’s tooth and blowball, and MSKCC puffball and wild endive.

In Europe dandelion was both food and pharmacy. EMA’s assessment report dates its use in German folk medicine to the sixteenth century, and Grieve notes it was much valued in the times of the English herbalists Gerard and Parkinson. By her day the root was dug commercially in autumn, and country druggists prided themselves on their dandelion juice, pressed from fresh roots. Grieve suggests that the liver reputation owed something to the doctrine of signatures, the idea that a plant’s appearance reveals its use, because the bright yellow flowers were a bilious hue. She also describes roasted dandelion coffee sold in vegetarian restaurants, dandelion wine made from the flowers in Berkshire and Worcestershire, and dandelion beer and stout drunk by furnace and pottery workers in the Midlands. Young leaves, blanched under a pot to soften their bitterness, were a spring salad, especially in France.

In the United States the dried root was official in the US Pharmacopeia. King’s American Dispensatory (1898) specified root gathered in autumn and described it as a stomachic and tonic with slightly diuretic and laxative actions, long supposed to relieve torpor and engorgement of the liver and spleen. It was frank about the limits. Professor King thought the plant’s virtues had been overrated, and the book warned that it could cause indigestion, wind, pain, and diarrhea in people with weak digestion and should not be used with an irritable or inflamed stomach or bowel. NCCIH notes that the flowers, leaves, and root have traditionally been used in Mexican and other North American medicine, and MSKCC records the use of dandelion in Chinese medicine to promote breast milk and to treat abscesses, especially of the breast. Older European texts went much further than modern regulators do: the British Herbal Pharmacopoeia of 1983, as summarized by EMA, recommended the root for cholecystitis, gallstones, jaundice, sluggish digestion with constipation, muscular rheumatism, and scanty urine.

Modern regulation has narrowed those claims. Germany’s Commission E, cited in EMA’s 2009 assessment report, gave a dose of 3 to 4 g of root with herb per cup, and German dandelion tablets made from dry extract have been on the market since 1976. WHO’s monographs on selected medicinal plants (volume 3, 2007), also summarized by EMA, recorded folk uses for diabetes, rheumatism, urinary infections, fever, insomnia, eye inflammation, sore throat, abscesses, and jaundice, and as a milk-promoter, laxative, and tonic. On 12 November 2009 EMA’s herbal committee adopted monographs on the leaf and on root with herb, limited to traditional use because no clinical studies were found. A separate root monograph followed on 24 November 2021. Reviews in 2019 found no new efficacy or safety data that would justify revising the leaf or root-with-herb monographs, apart from a correction to the quality standard, and in March 2026 EMA opened new calls for scientific data on both. One change is notable: in the 2021 root monograph, gallstones and other biliary disease moved from the contraindications to the warnings, because of a lack of pharmacovigilance, preclinical, and clinical data rather than any new evidence of safety.

Bitterness is the oldest explanation and the most plausible one. EMA notes that bitter principles are thought to increase secretions from the salivary and stomach glands by stimulating bitter receptors, the classic rationale for bitters before meals. In dandelion the bitterness has been linked to the sesquiterpene lactone taraxinic acid glucoside and its dihydro relative, along with p-hydroxyphenylacetic acid and β-sitosterol (EMA, citing Kuusi 1985). Old animal experiments support the bile tradition. A water decoction of dandelion leaves given into the small intestine of rats raised hourly bile volume by up to 40% (Böhm 1959), and a decoction given intravenously to dogs doubled bile flow over 30 minutes (Chabrol 1931), both as summarized by EMA. That bile-stimulating idea is also why EMA cautions against dandelion in gallstones and bile-duct obstruction. In rats, taraxinic acid glucoside protected the stomach lining against aspirin damage without changing acid secretion, but none of this has been measured in people taking dandelion tea.

The diuretic story rests on rats and on potassium. In a 1974 study by Rácz-Kotilla and colleagues, summarized by EMA, water extracts of the herb increased urine more than root extracts, and the highest dose, equivalent to 8 g of dried herb per kg of body weight, matched the effect of 80 mg/kg of furosemide; the response was not linear and fell off at the top concentration. Other teams could not confirm a diuretic effect, and purified root fractions only slightly raised urine volume in mice. Both EMA and MSKCC suggest that any diuretic action may come partly from the plant’s high potassium content, and EMA adds certain flavonoids, while noting that no study has confirmed this. One leaf infusion contained 519 mg of potassium per liter. In laboratory work, an alcohol extract of dandelion root triggered calcium signals in mouse kidney collecting-duct cells and dampened a kidney chloride channel in engineered human cells (Gerbino, cited by EMA), possible mechanisms that remain untested in people. The doses used in the rat studies were far above anything in a cup of tea.

Other laboratory effects are real but far from proven benefits. Inulin is a soluble fiber that feeds gut bacteria: dandelion root extract boosted the growth of 6 of 14 bifidobacteria strains in culture (Trojanová 2004, cited by EMA). A root extract blocked ADP-induced platelet clumping by up to 85% in human plasma in the test tube (Neef 1996), but a leaf infusion had no effect on platelets from healthy volunteers (Saulnier 2005). A water infusion weakly inhibited the starch-digesting enzyme α-glucosidase, needing several times the concentration of the drug acarbose (Önal 2005). In rats given dandelion tea, activity of the liver enzyme CYP1A2 fell to 15% of normal while the detoxifying enzyme UGT more than doubled (Maliakal and Wanwimolruk 2001). Extracts protected the liver of rats and mice against toxins and alcohol, reduced fat storage in cultured fat cells, and killed some cancer cell lines. EMA concluded that experimental support for the proposed uses is very limited, though the reported effects are not considered contradictory to the traditional uses, and none of these effects has been confirmed in people.

Digestion and appetite are the core traditional uses of Taraxacum officinale. EMA’s 2021 monograph accepts dandelion root as a traditional herbal medicine for the relief of mild digestive disorders such as a feeling of abdominal fullness, flatulence, and slow digestion, and for temporary loss of appetite, in adults and adolescents; its 2009 monograph accepts root with herb for the same complaints. For poor appetite, the root is taken half an hour before meals, and anyone whose symptoms last longer than two weeks is told to see a doctor. In many European countries dandelion is sold mainly in combination products and teas rather than on its own (EMA). These listings are explicitly based on long-standing use. EMA found no clinical studies of efficacy, and the indications were judged plausible on the basis of reference books and laboratory pharmacology rather than proven. Bitter greens and root teas before a meal are a reasonable thing to try for an occasionally sluggish stomach. Ongoing indigestion, weight loss, difficulty swallowing, or pain is a reason to see a doctor.

Increasing urine is the other European indication. EMA accepts dandelion leaf, root, and root with herb as traditional remedies to increase the amount of urine to flush the urinary tract as an adjuvant in minor urinary complaints, with plenty of fluid. Human evidence is thin and mixed. Clare and colleagues (Journal of Alternative and Complementary Medicine 2009) gave 17 volunteers 8 mL of a fresh-leaf alcohol extract three times in one day. Urination became more frequent in the five hours after the first dose and the ratio of urine passed to fluid drunk rose after the second, but the third dose changed nothing. In its 2019 review EMA pointed to the lack of blinding, the small numbers, self-recorded fluid intake and output, no correction for water in food, and limited baseline data. In 2026 Gavin, Caulfield, and Egan (International Journal of Sport Nutrition and Exercise Metabolism) gave 14 active young adults 1 liter of water with or without about 2.1 g of commercial dandelion root powder. Urine over four hours was 1,268 g with dandelion and 1,164 g without, a difference that was not statistically significant. Leaf extract and root powder differ, but neither study shows a reliable diuretic.

Liver support is dandelion’s best-known folk claim and its weakest modern one. Older texts recommended the root for jaundice, gallstones, and even progressive cirrhosis (EMA, citing Polish and British sources), and supplement labels still promise a liver cleanse or detox. The evidence consists of animal studies, such as reduced liver damage in rats given the solvent carbon tetrachloride, in mice given alcohol, and in mice fed a fatty diet (EMA, MSKCC). EMA found no human trials, and its monographs point the other way: they advise against medicinal dandelion in people who already have liver disease, gallstones, or bile-duct problems. MSKCC even lists a case of acute liver injury in a 36-year-old woman who drank a herbal liver detox tea containing dandelion, which settled after she stopped. There is no evidence that dandelion improves liver function in healthy people, and people with diagnosed liver disease are the group EMA specifically tells to avoid medicinal doses.

Many other uses have little support. MSKCC lists stimulating breast milk, diabetes, appetite, and increasing urination among dandelion’s purported uses and says the other uses have not been studied by doctors to see if they work. LactMed notes that dandelion is a purported galactogogue, a milk-promoting herb, but that no scientifically valid clinical trials support this. For blood sugar, powdered whole plant lowered blood glucose in normal rabbits but not in diabetic ones, and the α-glucosidase effect seen in the test tube was weak (EMA), although MSKCC records a case of low blood sugar after eating dandelion. Weight-loss claims rest on cultured fat cells, in which a root extract cut fat accumulation by about 20% (González-Castejón 2014, cited by EMA). NCCIH notes that oral dandelion is promoted for indigestion and oral and topical products for joint pain, but finds no compelling evidence for any health condition and only preliminary laboratory work on anti-inflammatory, antioxidant, and antiviral effects. Any weight lost through extra urine is water, not fat.

Cancer claims deserve particular care, because dandelion root extract is widely promoted online. In the laboratory, an aqueous root extract killed more than 95% of colon cancer cells within 48 hours and slowed the growth of human colon tumors in mice by more than 90% (Ovadje and colleagues 2016, summarized by EMA), and MSKCC lists similar results in melanoma, leukemia, and pancreatic cancer cell lines. MSKCC also cites preclinical evidence that an extract of the related Taraxacum mongolicum has estrogen-like activity, increasing the growth of hormone-sensitive breast cancer cells and the uterine weight of young rats, which is a reason for caution rather than enthusiasm in hormone-sensitive cancers. A few case reports describe possible benefit in people with blood cancers, but MSKCC says it is unclear whether dandelion was responsible, and it concludes that clinical trials are needed to show when dandelion may be safe and effective. Dandelion root is not a treatment for any cancer, and anyone considering it during cancer care should talk to their oncology team first, given its possible effects on drug-metabolizing enzymes.

EMA’s monographs give specific traditional doses for adults and adolescents. For dandelion root (2021), the options are a decoction of 1 to 5 g of cut root in 150 ml of water, two or three times a day; fresh root juice, 4 to 8 ml three times a day; a 1:1 liquid extract in 30% alcohol, 2 to 8 ml three times a day; or a 1:5 tincture in 45% alcohol, 5 to 10 ml three times a day. EMA notes that a tablespoon of cut root weighs about 7.2 g. For root with herb (2009), it lists 3 to 4 g as a decoction or 4 to 10 g as an infusion up to three times a day, a 300 mg dry-extract tablet twice daily, or 10 ml of fresh pressed juice three times daily. For the leaf, it gives 4 to 10 g as an infusion, or 4 to 10 ml of liquid extract, three times a day, or 5 to 10 ml of fresh leaf juice twice a day. For urinary use, plenty of fluid is part of the treatment. Courses are short: the root monograph advises seeing a doctor if symptoms last more than two weeks. None of these preparations is recommended under age 12.

As a food, the leaves are best picked young. Grieve warns that full-grown leaves are too bitter for salad, and blanching young leaves under a pot makes them milder, though PFAF notes that blanched leaves also contain fewer vitamins and minerals. Grieve also boils young leaves like spinach; PFAF describes digging the roots of two-year-old plants in autumn, drying and roasting them for a caffeine-free coffee substitute; the flowers go into wine, and unopened buds into fritters. A cup of chopped raw greens (55 g) supplies about 428 micrograms of vitamin K, more than three times the daily amount the NIH Office of Dietary Supplements sets for adult men. Gather only from ground you know: away from roads, industrial sites, dog-walking routes, and lawns treated with weedkillers, given the metal levels found in some wild dandelions. Wash leaves well, and wear gloves if handling the plant irritates your skin; PFAF notes reports of dermatitis from touching dandelions, probably caused by the latex.

Practical points: check the label for the plant part, because leaf, root, and root-with-herb products are listed for different uses and taste quite different, and many dandelion teas are blends. A single-herb product with a stated amount per dose is easier to judge than a multi-herb detox or slimming blend, the kind of product behind several published case reports of harm. Drink plenty of fluid when using dandelion to increase urine, and do not use it that way if a doctor has told you to limit fluids. Do not stack several bitter or flushing teas at once. Stop and see a doctor if you develop fever, painful urination, cramps, or blood in the urine, as EMA advises, or if you notice yellowing of the skin or eyes. Very large amounts can matter: in the case report by Moriarty and colleagues, a man with kidney failure who drank 10 to 15 cups of dandelion tea a day for six months developed oxalate deposits and gangrene of his fingertips.