evidence: A note about the poison. Rats (and gerbils, hamsters, and mice) cannot vomit. Unlike my dogs. It turns out that corn gluten and salt can kill rats and mice by stopping up their digestive system and causing dehydration. The rats become comatose and die in their burrows. Although poisonous to rats, corn gluten won’t hurt other wildlife – and other wildlife can eat any dead rats and not be poisoned themselves.