In most professional literatures, all parts of Cascabela Thevetia (Syn.
Thevetia Peruviana) are refered to as highly poisonous. This includes
the fruit pulp. In an attempt to find-out about the fruit toxicity, I
have observed how the fruit develops. When mature, it falls on the
floor, and its pulp has a sweet smell (I did not taste it). This is a
common feature among fruits which disperse their seeds by grazing
animals eating them, including mammals, although not necessarily
equally safe to all such animals.

Although seeds and plant parts are all toxic, there have been some
inconclusive results regarding the edibility of the fruit itself. An
example of plant poisoning article in this website

http://members.tripod.com/~Prof_Anil.../poiso031.html

refers to fruit toxicity in one part, while it says that it is
occasionally eaten by humans in another part. Are there different
varieties of the same plant (one produced the poisonous fruit, the
other does not)? In the wild, which animal safely eats the fruit, and
is that related to an edible or poisonous variety?