Our dog sneaked upstairs and ate all my daughters easters eggs last year, six of them, mostly large ones! I was outside gardening. He must have gulped them down at high speed as he had been outside with me not long before. He was taken in for monitoring to begin with and then had his stomach 'pumped' well made to eat nasty things and kept in. I was told that all dogs are allegic to chocolate as there is an enzyme in it which, dogs cannot digest. So I don't think it is an allergy thing. We laughed about it afterwards, when he was ok. But needless to say, we are more careful with our chocolate now. Mind you, my husband looked up on the internet all the things dogs are allergic too, and you'd never leave the house!! Our old dog, bless him was allergic to grass, and once had a fit at Badminton Horse Trials in the long grass (before we had allergy tests). He ended up on steriods, bless him. You can't plan for that allergy. Glad your dog's ok. Tou'd think they'd have dog sense wouldn't you.