What are the side effects of taking metronidazole?
Nov 25, 2025
Source: Cainiu Health
Dr. Huang Yuhong
Introduction
Metronidazole, also known as xiaxiaozuo, may cause side effects including gastrointestinal discomfort, nervous system reactions, allergic reactions, blood system abnormalities, and a metallic taste in the mouth. Gastrointestinal discomfort: Metronidazole may irritate the gastrointestinal mucosa, leading to digestive symptoms such as nausea, vomiting, abdominal pain, and diarrhea, which are usually related to direct drug irritation or disruption of intestinal flora.
Metronidazole, also known as "jiaxiao zuo," may cause side effects including gastrointestinal discomfort, neurological reactions, allergic reactions, blood system abnormalities, and a metallic taste in the mouth. Detailed analysis is as follows:
1. Gastrointestinal discomfort: Metronidazole may irritate the gastrointestinal mucosa, causing digestive symptoms such as nausea, vomiting, abdominal pain, and diarrhea. These symptoms are usually related to direct drug irritation or disruption of intestinal flora. It is recommended to take the medication half an hour after meals to reduce gastrointestinal irritation. Seek medical attention promptly if symptoms persist or worsen.
2. Neurological reactions: Some patients may experience neurotoxic reactions such as headache, dizziness, ataxia, or limb numbness. Long-term high-dose use may trigger seizures or peripheral neuropathy. Avoid driving or working at heights during treatment. Discontinue the drug immediately and inform your doctor if any abnormalities occur.
3. Allergic reactions: A small number of patients may develop skin allergies such as rash, itching, or urticaria. In severe cases, laryngeal edema or anaphylactic shock may occur. Inform your doctor of any history of allergies before taking the drug. Close monitoring is required during initial use. Discontinue the drug immediately and seek emergency treatment if difficulty breathing occurs.
4. Blood system abnormalities: Long-term use of metronidazole may suppress bone marrow hematopoietic function, leading to changes such as decreased white blood cells or reduced platelets. Regular blood tests are necessary for long-term users. Seek medical attention promptly if symptoms such as fever or bruising occur.
5. Metallic taste in the mouth: Metabolites of metronidazole may cause a persistent bitter or metallic taste. Although this does not affect treatment efficacy, it may reduce patient compliance. This can be alleviated by dividing doses, sucking on ice chips, or using flavoring agents.
During metronidazole therapy, strictly follow medical instructions, avoid alcohol to prevent disulfiram-like reactions, maintain a light diet, regularly monitor complete blood counts, and seek immediate medical care if serious side effects occur.
