Is your garden poisonous?
Last week I had a dog called Josie come in because she was tremoring all over and appeared very agitated and distressed. She was very close to seizuring now but had been fine earlier in the evening.
I gave her some medication to make her vomit and along with some bits of plastic bag (she had also got into a nappy earlier in the day, so yes he was a garbage guts) there was some small pieces of plant material and very small seeds.