Gastrointestinal reactions are most common after metronidazole administration, manifesting as nausea, vomiting, loss of appetite, abdominal cramps, and generally do not affect other systemic systems; neurological symptoms include dizziness, limb numbness, ataxia, polyneuritis, etc. In a few cases, urticaria, skin flushing, itching, etc. can occur, as well as symptoms such as metallic taste in the mouth and leukopenia. These adverse reactions are reversible and can recover on their own after discontinuation of the drug. Metronidazole has contraindications. It is contraindicated in women during pregnancy and lactation, and should be used sparingly in patients with active central nervous system disorders or hematologic disorders, and should be reduced in patients with hepatic insufficiency because it is metabolized by the liver.