An extract of the plant oleander may offer potential as an anti-cancer treatment. Researchers at the University of Texas have been examining the properties of a derived substance and find that it inhibits the spread of a cancer growth agent and injects oxygenated free radicals into the impacted tissues, which cause cell death. Normally, presence of free radicals in the body is not positive and is associated with oxidation, aging, and cancer initiation.
However, in its natural state, all parts of the plant are very poisonous with alkanoids and glycosides and can be fatal to humans as well as grazing animals. It is ignored by omnivorous browsing deer for this reason.
Nevertheless, Pliny the Elder in Historia Naturalis observed:
The rhododendron (referring to oleander and the related desert rose) has not so much as found a Latin name among us, its other names being "rhododaphne" and "nerium." It is a marvellous fact, but the leaves of this plant are poisonous to quadrupeds; while for man, if taken in wine with rue, they are an effectual preservative against the venom of serpents. Sheep too, and goats, it is said, if they drink water in which the leaves have been steeped, will die immediately.