It is sometimes grown as a medicinal and ornamental plant. It is used as a traditional medicine in Indonesia, Thailand, Malaysia and parts of Africa including Nigeria. The young leaves are crushed, and the resulting liquid can be used to treat skin wounds.In traditional medicine of Thailand the plant is used for the treatment of wounds, rashes, diabetes, and as insect repellent. It has antifungal and antibacterial properties.
A recent review indicates that the ethno-pharmacological, funcigicidal, nematicidal importance of the plant and its use as a fallow species and as a soil fertility improvement plant in the slash and burn rotation system of agriculture has contributed to its continued use and spread in Nigeria.
A protein extract from the leaves was in use as a poultry feed during the civil war in Nigeria. Siam weed is not palatable to cattle and large tracts of extensively managed pasture land have been abandoned because of uncontrollable Siam weed infestation.
Leaves of Siam weed are reported to be useful in controlling the weevil Cylas formicarius and the butterfly Phtorimae operculella in sweet potato, the nematode Heterodera marioni in black pepper, as well as nematodes in sugar cane and tomato.
Siam weed is used as a medicine for intestinal pains, colds and cough in the Caribbean region; in Ivory coast, for healing wounds, as a purgative, a remedy against cough, malaria, smallpox and yellow fever. In Thailand, C. odorata is traditionally used to stop bleeding.