eucalyptus

Any tree of a group belonging to the myrtle family, native to Australia, where they are commonly known as gumtrees. About 90% of Australian timber belongs to the eucalyptus genus, which contains about 500 species. The trees have dark hardwood timber which is used for heavy construction work such as railway and bridge building. They are mostly tall, aromatic, evergreen trees with pendant leaves and white, pink, or red flowers. (Genus Eucalyptus, family Myrtaceae.)

Compounds isolated from eucalyptus leaves were found in 1996 to be highly effective in killing Streptococcus mutans, the bacteria found in the mouth that cause dental decay.