A few of the commonly noted side effects of Metronidazole for dogs and cats are neurologastro-intestinal disorder, lethargy, weakness, neutropenias, hepatoxicity, and hematuria. Cases of anorexia, nausea, excessive salivation, gagging, regurgitation and diarrhea are also reported. Harmful effects of metronidazole for dogs and catsnormally affect the brain and its equilibrium. Drowsiness, rashes and incoordination are other side effects. There are a few rare side effects such as loss of appetite, vomiting, staggering or difficulty in walking, involuntary and constant eye movements, lethargy and seizures. Occasionally death can also occur and therefore stop administration of the drug as soon as any side effects are noted.