This shrub is very commonly grown here by the Mediterranean. Its Nerium oleander -common oleander.
Although it has very pretty flowers and glossy green leaves, it very, very toxic - apparently eating a single leaf will kill an adult and the sap will cause a rash in many people. All parts of the plant are poisonous- including the very attractive flowers.
The toxin that acts on the heart and causes death by heart attack or liver or kidney failure - so its definitely in the category of look don't touch or eat.