UPAs

Upas is a common name for the upas tree, Antiaris toxicaria, a tropical evergreen tree in the Moraceae family. The term derives from Malay and Indonesian upas, meaning poison. The tree is native to tropical Africa and Asia and has a wide tropical distribution, often found in forests, along riverbanks, and in secondary growth. It can grow to a substantial size and contains a milky latex in its bark that is toxic.

Traditionally, the latex was used to prepare hunting poisons for arrows and to poison fish. Indigenous peoples in various regions have long explored these preparations, sometimes combining the latex with other plant materials. In Western travel literature, the upas tree became famous for claims that it emits deadly gases or vapors that kill nearby animals and people. Modern science finds no credible evidence for the existence of a noxious airborne fume emitted by the tree; reports likely reflect misinterpretations of the latex’s irritant effects or observations of animals dying after contact or ingestion.

Ecology and human uses are modestly documented. The tree has been used for timber in some areas and features in traditional medicine and cultural lore. Despite the historical aura of danger, the primary hazard associated with upas relates to handling the latex rather than any persistent airborne toxin.

In summary, upas refers to a tropical tree whose poisonous latex has driven its notoriety in both indigenous practice and historical travel literature, though the idea of a poisonous gas emanating from the tree is a myth.