Prescription drug · Used for infections

Metronidazole (Flagyl) side effects

This side effect is printed on the FDA label for Metronidazole. It was a question in our daily quiz, where you pick the real side effect from four choices.

Vomiting and flushing if you drink alcohol

The reaction can hit during treatment and for days after. The label says to wait three days after the last dose.

From the FDA label

“Use of oral metronidazole is associated with a disulfiram-like reaction to alcohol, including abdominal cramps, nausea, vomiting, headaches, and flushing.”

Metronidazole label, updated Aug 26, 2026 · Read the full label on DailyMed

What to watch for

Skip alcohol, and products containing propylene glycol, during treatment and for 3 days after.

34 reports to the FDA's adverse event system mention an alcohol reaction. A report is not proof the drug caused it. See the query

From quiz No. 9 · October 3, 2026 · Play that quiz →

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Not medical advice. Don't stop or start a medication because of a quiz. Talk to your doctor or pharmacist. Label text and report counts from openFDA. Not affiliated with any drug maker.