Metronidazole
Also known as: Flagyl
What it's for
Metronidazole is an antibiotic for infections caused by bacteria and parasites. It treats dental infections, skin infections, pelvic infections, and some stomach bugs.
Comes as: Tablets or liquid
How to take it
- Adults: Usually 400mg 2 or 3 times daily, or as prescribed.
- Take with or after food.
- Swallow tablets whole with water.
- Complete the full course.
Doses here are typical. Always follow the instructions from your prescriber or on the packet — they come first.
Common side effects
- Feeling sick or vomiting
- Metallic taste in your mouth
- Loss of appetite
- Diarrhoea
The leaflet inside the packet lists all known side effects.
Important safety points
- Do NOT drink alcohol during treatment and for 48 hours after - causes severe sickness
- May make you feel dizzy - take care when driving
- Tell your doctor if you have liver problems
- Can interact with blood-thinning medicines
Get medical help urgently if…
- You have numbness or tingling in your hands or feet
- You have seizures
- You have severe stomach pain
- You have signs of an allergic reaction
Call NHS 111 for urgent advice, or 999 if someone is seriously unwell.
Before you act on anything here
This page is general information, written to help you understand — it is not personal medical advice and it cannot tell you what is right for you. Talk to your own GP, pharmacist or nurse about your own health.
- Need help now but it's not an emergency? Call NHS 111 or use 111.nhs.uk.
- Emergency? Call 999 or go to A&E.