Flagyl 400

Tablet
PRESCRIPTION MEDICINE

Flagyl 400 is a tablet that contains Metronidazole 400 mg. Metronidazole is a anti-amoebic and antibacterial: treats amoebic dysentery, gut, dental and vaginal infections.

Ingredient (salt)Amount
Metronidazole400 mg

What it is used for

Treats amoebic dysentery, gut, dental and vaginal infections.

How it works

A nitroimidazole for amoebic and giardia infections, bacterial vaginosis, dental abscesses and anaerobic infections, including C. difficile.

How to take it

Usually 400 mg two or three times a day with or after food, for 5 to 7 days.

Common side effects

  • Metallic taste
  • Nausea
  • Dark urine
  • Loss of appetite

Get medical help straight away if

  • Numbness or tingling in hands or feet
  • Fits
  • Severe diarrhoea
  • Dark urine with yellow skin

Be careful

Avoid alcohol during and for 2 days after the course; metallic taste is common.

Other medicines and interactions

Do not drink alcohol during the course and for 3 days after (severe flushing, vomiting and palpitations). Strengthens warfarin; can raise lithium levels.

Pregnancy and breastfeeding

Can be used in pregnancy when needed (high single doses avoided). Passes into breast milk; a doctor may advise a short pause after single high doses.

Same composition, other brands (1)

Metrogyl 400

Ask your doctor or pharmacist before switching brands.

Common questions

What is Flagyl 400?

Flagyl 400 is a tablet containing Metronidazole 400 mg.

What is Flagyl 400 used for?

Treats amoebic dysentery, gut, dental and vaginal infections.

How should I take Flagyl 400?

Usually 400 mg two or three times a day with or after food, for 5 to 7 days. Always follow the dose your doctor or the pack gives.

What are the side effects of Flagyl 400?

Common side effects include: Metallic taste, nausea, dark urine, loss of appetite. Get medical help straight away for: Numbness or tingling in hands or feet, fits, severe diarrhoea, dark urine with yellow skin.

Does Flagyl 400 need a prescription?

Yes. In India it is a prescription (Schedule H) medicine, so a pharmacist should sell it only with a doctor's prescription.

Can I take Flagyl 400 in pregnancy or while breastfeeding?

Can be used in pregnancy when needed (high single doses avoided). Passes into breast milk; a doctor may advise a short pause after single high doses.

What are the substitutes for Flagyl 400?

Brands with the same composition: Metrogyl 400. Ask your doctor or pharmacist before switching.

Sources and further reading

NHS (UK National Health Service) and MedlinePlus (US National Library of Medicine) are free, reviewed medicine guides. Brand names and doses there may differ from India.

Composition checked against pack details from large Indian online pharmacies. Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. This page is a plain-language summary written from standard prescribing information and the public guides linked below. Brands sometimes change their formula, so always check the composition printed on the pack. Doses here are typical adult doses; yours may differ. Do not start, stop or change a medicine without your doctor or pharmacist, and keep all medicines away from children. In an emergency, call 112 (India) or your local emergency number.