Does Metronidazole Make Dogs Sick?

Does Metronidazole Make Dogs Sick? Metronidazole can lower the amount of healthy gut bacteria in dogs, which in turn may cause more diarrhea. Its bitter flavor may also cause more drooling than usual. Other common side effects of metronidazole are: Nausea/vomiting. Is metronidazole hard on a dog’s stomach? Common side effects of metronidazole in dogs