We picked up a stray dog two days ago, and she was INFESTED with lice. The vet recommended generic flea-drops, so my sister went to the store and bought some Hartz for the dog, being careful to buy the drops for 15-30lb dogs (she’s 17lbs). My husband put the drops on her at 2:30 today; she was lethargic after that, and around 5:00, she started puking. She puked five times between 5:00 and 5:30. We called the vet who recommended a bath, so we bathed her THOROUGHLY, and she’s puked 3 more times between 5:30 and now (9:00). We haven’t been able to get her to drink any water, and she’s also uninterested in food despite being underweight. She perked up after the bath, so we’re optimistic, but we were shocked at her reaction.