I think all parts contain the alkaloid poison, though foliage, flowers and the rarely produced berries are most toxic. Most mammals including ourselves would find it toxic of course.

I can't really imagine any dog wanting to eat in the first place. Animals have far more sense when it comes to what is and isn't edible.

And it's amazing what dogs an eat without ill effect! Just might 'hurry' the morning processes, that's all! Worthy