Cockleburs (Xanthium) are a genus of flowering plants in the family Asteraceae, native to the Americas and eastern Asia. The Common Cocklebur (Xanthium strumarium) is a native of North America where in the past the (now extinct) Carolina Parakeet fed on the seeds. It has become an invasive species worldwide. It invades agricultural lands and can be poisonous to livestock, including horses, cattle, and sheep.

Xanthium sibiricum patrin ex Widder (Compositae) is an annual herb which grows all around China. Chemical investigations of its roots resulted in the identification of 15 compounds: stigmast-4-en-6β-ol-3-one (1), β-sitostenone (2), β-sitosterol (3), nonadecanoic acid (4), 5α,8α-epidioxy-22E-ergosta-6,22-dien-3β-ol (5), scopoletin (6), Jatrocin B (7), (±)syringaresinol (8), 9,9'-O-di-(E)-feruloyl-(-)-secoisolariciresinol (9), cleomiscosin A (10), cleomiscosin C (11), N-trans-feruloyl tyramine (12), daucosterol (13), 5-methyluracil (14) and uracil (15).Structures were elucidated by spectroscopic (NMR and MS) methods and confirmed by comparing with reference samples and literature data.