Rough cocklebur

Xanthium strumarium — rough cocklebur, cocklebur, clotbur or Noogoora burr — is an annual herb in the daisy family (Asteraceae), genus Xanthium, and the only species of that genus in Vietnam. The plant grows 50–120 cm tall, with grooved, hairy stems marked with purple spots, often purplish at the base. The alternate leaves are broadly ovate to triangular, 5–20 cm long and 4–16 cm wide, heart-shaped at the base, with irregular coarse teeth or shallowly three-lobed, on a petiole 3–10 cm long. The species is monoecious, with separate unisexual heads: the staminate (male) heads sit at the tips of the upper branches and the pistillate (female) heads in the lower leaf axils, wind-pollinated. The fruit is a bur-like achene, ovoid to spindle-shaped, 1–1.5 cm long, covered in stiff hooked spines and containing two seeds; the hooked bur clings to animal fur and clothing and is buoyant, so it disperses both on mammals and on water. Flowering and fruiting usually occur from July to October.

Updated by lebachungtdh@gmail.com · 10/12/2026

Rough cocklebur is widespread worldwide: some sources place its origin in southern Europe and Asia, while others (Flora of China, Flora of North America) consider it American and an early introduction to Eurasia; it now grows wild on waste ground, roadsides, river banks and cultivated land throughout Vietnam. It is a troublesome weed and a hazard to livestock: the seeds and seedlings contain carboxyatractyloside, an extremely toxic compound that damages the liver, so poisonings of pigs, cattle and sheep are not rare. In return, the fruit (known in Chinese medicine as cang er zi) and leaves are a traditional medicine in Vietnam and China: anti-allergic and anti-inflammatory, used for allergic rhinitis and foul nasal discharge, hives, boils, sores, eczema, joint and rheumatic pain, headache, toothache, dysentery and diarrhoea, at a decoction dose of 6–12 g per day. A decoction of the fruit is used as a mouthwash for toothache and applied for ringworm and tinea. Chemically the fruit contains sesquiterpene lactones (xanthinin, xanthumin, xanthatin), fatty oil, alkaloids and a blood-glucose-lowering glycoside, and the leaves accumulate iodine (about 200 micrograms per gram). Studies show that xanthatin and xanthinin have antibacterial, antifungal, anti-allergic, antipyretic, diuretic and sedative activity and are under further investigation for anti-inflammatory and anticancer effects.

Updated by lebachungtdh@gmail.com · 10/12/2026