Chromolaena odorata is a shrub of the sunflower family native to North America, from Florida and Texas to Mexico and the West Indies. It is an invasive weed of field crops in Africa and Asia where it has been introduced. It is now found all over tropical Asia, western Africa, and in parts of Australia. Other names for the plant include Siam weed and Christmas bush, and Common Floss Flower. It is sometimes grown as a medicinal and ornamental plant. It is used as a traditional medicine in Indonesia. The young leaves are crushed, and the resulting liquid can be used to treat skin wounds.
It was earlier taxonomically classified under the genus Eupatorium, but is now considered more closely related to other genera in the tribe Eupatorieae.