Dandelion

Dandelion (Taraxacum officinale) is a long-lived perennial herb forming a basal rosette of deeply toothed leaves — the source of the name 'lion's tooth'. Solitary yellow flower heads on hollow stalks open in daylight and close in dull weather, later ripening into the familiar 'dandelion clock' of plume-bearing fruits dispersed by wind. The taproot is long, fleshy and filled with milky latex; the flowering stalk reaches only 5–40 cm.

According to Plants of the World Online (Kew), the native range spans Macaronesia, Europe to Siberia and North-West Africa; from there it has spread across temperate North and South America, Oceania and Asia. It is a taxonomically complex aggregate of hundreds of apomictic microspecies, and botanists often treat it as the collective Taraxacum officinale agg. (Taraxacum sect. Taraxacum) rather than a single species.

The root stores inulin — a fructan polysaccharide making up 2–40% of dry weight, lowest in early spring and highest in autumn — together with taraxasterol, taraxacin, sterols and phenolics; the leaves are rich in carotenoids (β-carotene, lutein), vitamin C and K, and minerals (potassium, calcium, iron). Latex contains bitter lactucin and taraxacoside, which stimulate digestion. Inulin is a prebiotic that resists small-intestinal digestion and feeds beneficial colonic bacteria.

Dandelion is used as leaf and root tea, roasted root as a caffeine-free coffee substitute, young leaves raw or cooked, and flowers in wine. European traditional medicine uses the root as a diuretic, cholagogue and digestive aid, and both the EMA and ESCOP hold root monographs. A human study found a single-day diuretic effect of leaf extract (Clare, 2009); reviews note antioxidant, anti-inflammatory and glucose-lowering potential, though high-quality clinical evidence remains limited (Schütz, 2006; González-Castejón, 2012).

Dandelion is generally considered safe; the main adverse reactions are allergy in people sensitive to Asteraceae and, rarely, mild digestive upset. Those taking diuretics or glucose-lowering drugs, or with gallstones, should seek professional advice. For conservation, the IUCN Red List has not globally assessed the species (NE), and extinction-risk modelling (Bachman et al., 2024) predicts it is 'not threatened' with confident certainty; it is a cosmopolitan weed that in many places is controlled rather than conserved.