Indigenous to Europe, dandelion is now widespread throughout North America. Hundreds of subspecies of Taraxacum officinale with distinctive appearances are found in the temperate regions of Europe and Asia as well. Dandelion is a common weed, but it is heralded for both its culinary and medicinal value. It is consumed mainly as a food, and its leaves contain the highest vitamin A content of all greens. This plant is also a source of wine, beer, and coffee substitutes.

In traditional medicine, dandelion roots and leaves are used largely in treatments for hepatic disorders. In Europe, herbalists incorporate it into remedies for liver congestion, fever, skin ailments, eye problems, diarrhea, fluid retention, and heartburn. The leaves produce a transient diuretic effect while the roots act as an appetite stimulant and digestive aid. Chinese medicinal practitioners traditionally used dandelion to treat digestive problems, appendicitis, and breast cancer. Today, herbal practitioners still tout dandelion leaves as an effective diuretic and weight-loss agent.

Dandelion is generally considered nontoxic and devoid of adverse side effects. Pharmacological studies confirm that dandelion stimulates diuresis, and acts on the liver and digestive processes. Taraxacin, an undefined bitter principle in dandelion, may be responsible for its therapeutic effects on digestion. However, there is only limited scientific evidence supporting the efficacy of dandelion for its varied traditional uses. Even though numerous active principles have been isolated from the rhizomes and roots, only a few structure-activity relationships have been established.

Dandelion is a hardy, variable perennial that can grow to a height of nearly 12 inches. Its short rhizome divides at the crown into a tapered, multi-headed taproot. It has a distinctive basal rosette of deeply notched, toothy, spatula-like leaves that are shiny and hairless. Each rosette is capped by a head of composite bright yellow flowers. The grooved leaves funnel the flow of rainfall into the tapered root.

Dandelion flowers are light-sensitive, characteristically opening in the morning and closing in the evening and during gloomy weather. The roots are fleshy and brittle, with a dark brown exterior, and filled with a white milky latex that is bitter and slightly odorous.

• leaves
• roots 

Acids (e.g., caffeic acid, p-hydroxyphenylacetic acid, chlorogenic acid, linoleic acid, linolenic acid, oleic acid, palmitic acid), resin (undefined bitter complex, taraxacin), terpenoids (sesquiterpene lactones, or bitter substances: e.g., taraxinacetyl-1'-O-glucosides, 11,13-dihydrotaraxinacetyl-1'-O-glucosides, taraxacolide-1'-O-glucosides, taraxinic acid), flavonoids, vitamin A (14,000 IU/100 g leaf), carotenoids, choline, mucilage, inulin, pectin, phytosterols, sugars, potassium.

Commercial preparations of dandelion are available as liquids and solids for oral use. Root preparations are made from dandelion root harvested in autumn, and the roots are then air-dried. Both dried leaves and dried aerial parts are collected before the flowering season. Root products are preferably prepared from large, fleshy, and well-formed roots on plants that are two years old. Dandelion products when stored should be protected from light and moisture.

Traditional uses: mild diuretic and weight loss aid (leaf preparations); laxative, cholagogue (stimulates flow of bile to duodenum), muscular rheumatism and other rheumatic ailments, cholecystitis (gallbladder inflammation), gallstones, jaundice, dyspepsia with constipation, oliguria (diminished urination), poor circulation, liver and gallbladder disorders, hemorrhoids, congestion in the portal system, gout, skin ailments

Conditions: dyspepsia, infections of urinary tract, kidney stone and gravel formation, liver and gallbladder complaints, loss of appetite, disturbances in bile flow, stimulation of diuresis, diabetes

Clinical applications: loss of appetite, dyspepsia, bile flow disorders, diuretic

An aqueous extract of dandelion showed antitumor activity in vitro. Oral administration of dandelion extracts, particularly herb extracts, produced diuretic activity in rats and mice. Dried dandelion herb (2 g/kg, or 50 ml) exhibited a diuretic effect comparable to that of 80 mg/kg furosemide (Lasix) without the potentially adverse side effects of Lasix.

An alcohol extract of dandelion was given to mice inoculated with Ehrlich ascites cancer cells, with the test animals receiving dandelion over a 10-day period. The extract significantly suppressed the growth of cancerous cells within one week after treatment. In other research, dandelion stimulated production of antibodies to active polypeptides in tumor-induced ascites fluid in mice.

Dandelion and one of its constituents, inulin, showed hypoglycemic activity in normoglycemic but not in alloxan-treated hyperglycemic (diabetic) rabbits. The blood-sugar-lowering effect of dandelion may result from stimulation of pancreatic beta-cells, the mechanism responsible for the hypoglycemic activity of the sulfonylureas. In another investigation, a dandelion root extract produced moderate anti-inflammatory action against carrageenan rat paw edema.

• Dried leaf infusion: 4 to 10 g tid
• Dried root (infusion or decoction): 2 to 8 g tid
• Herb: 4 to 10 g tid
• Leaf tincture (1:5) in 30% alcohol: 5 ml tid
• Powdered solid extract (4:1): 250 to 500 mg/day
• Root tincture (1:2) fresh root in 45% alcohol: 5 ml tid

Dandelion is considered safe even in large quantities. Dandelion can be used for an unlimited duration.

The toxicity of this plant is extremely low. It is reportedly free of adverse side effects when used both externally and internally. LD₅₀ values (mice, I.P.) for the root and herb are 36.8 g/kg and 28.8 g/kg, respectively. Rabbits given dandelion extracts by mouth 3, 4, 5, and 6 g/kg body-weight for periods of up to one week showed neither visible signs of toxicity nor behavioral changes.

However, the bitter substances in this plant can cause gastric hyperacidity in some individuals. Though rare, contact allergic reactions can occur in response to sesquiterpene lactones in the latex. Also, dandelion has a weak sensitizing capacity.

Susceptible individuals may develop contact allergic reactions to dandelion; however, ingestion does not appear to cause allergic responses. Pregnant and lactating women can use dandelion safely if their intake is limited to quantities used in foods.

Dandelion may precipitate closure of the biliary ducts, gallbladder empyema (inflammation), and ileus. Individuals with biliary conditions and gallstones should first consult with a doctor before ingesting dandelion.

Although the components of dandelion have diuretic properties (Blumenthal 2000), no clinically significant interactions between this herb and diuretic or other medications have been reported in the literature.

The high mineral content of Taraxacum mongolicum, Chinese dandelion, may interfere with the absorption of quinolone antibiotics. In a rat study, concurrent dosing of aqueous Taraxacum mongolicum extract (2 g/kg) and ciprofloxacin (20 mg/kg po) lowered the maximum plasma concentration of ciprofloxacin by 73% (Zhu et al. 1999). It is not known if Taraxacum officinale, European or common dandelion, would interact similarly with quinolone antibiotics and reduce the blood levels of these drugs.

In Britain, dandelion is included in the General Sale List (GSL). The Council of Europe classifies this herb as a natural source of food flavoring (category N2) approved as an additive to foodstuffs in small quantities. Dandelion is listed as an approved herb in The Complete German Commission E Monographs.

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Baba K, Abe S, Mizuno D. Antitumor activity of hot water extract of dandelion, Taraxacum officinale-correlation between antitumor activity and timing of administration [in Japanese]. Yakugaku Zasshi. 1981;101(ISS 6):538-43.

Blumenthal M, ed. Herbal Medicine Expanded Commission E Monographs. Newton, Mass: Integrative Medicine Communications; 2000:79-80.

Blumenthal M, ed. The Complete German Commission E Monographs. Boston, Mass: Integrative Medicine Communications; 1998:118-120.

Davies MG, Kersey PJ. Contact allergy to yarrow and dandelion. Contact Dermatitis. 1986;14 (ISS 4):256-7.

Dorland's Illustrated Medical Dictionary. 25th ed. Philadelphia, Pa: W.B. Saunders; 1974.

Grieve M. A Modern Herbal. Vol. I. New York, NY: Dover; 1971:249-255.

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Mascolo N, et al. Biological screening of Italian medicinal plants for anti-inflammatory activity. Phytotherapy Res 1987:28-29.

Murray MT. The Healing Power of Herbs. 2nd ed. Rocklin, Calif: Prima Publishing; 1995: 86-91.

Newall C, Anderson L, Phillipson J. Herbal Medicines: A Guide for Health-care Professionals. London, England: Pharmaceutical Press; 1996:96-97.

Racz-Kotilla E, Racz G, Solomon A. The action of Taraxacum officinale extracts on the body weight and diuresis of laboratory animals. Planta Med. 1974;26: 212-217.

Tyler V. The Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. 3rd ed. New York, NY: Pharmaceutical Products Press; 1993:109-110.

Yamashita K, Kawai K, Itakura M. Effects of fructooligosaccharides on blood glucose and serum lipids in diabetic subjects. Nutr Res. 1984;4:491-496.

Zhu M, Wong P, Li R. Effects of Taraxacum mongolicum on the bioavailability and disposition of ciprofloxacin in rats. J Pharm Sci. 1999;88(6):632-634.