The oleander shrub is native to the Mediterranean region but is now grown in most tropical and subtropical areas of the world in dry and sunny locations.
Some people call it rose laurel. It has attractive red, pink, white or yellow flowers, but it is a highly toxic plant. It contains oleandrin, which causes nausea, vomiting, a reduced heart rate and sudden death.
It only takes a few leaves to kill a small child, and all parts of the plant are poisonous!
There have been numerous press reports of murders and suicides involving oleander plants. Some of these are discussed in Amy Stewart's book Wicked Plants.
Those of us who garden in cold climates cannot grow it, so we just enjoy the pretty flowers when we take trips to Caribbean island resorts or other warm vacation spots. However, all of us should be careful when using any flowers as a garnish, and we should always instruct children never to eat anything when in the garden without an adult. Even the commonly grown azaleas and rhododendrons, foxgloves, lobelias, lantanas, hellebores and hydrangeas, as well as hundreds of other flowering plants can make people sick.