NutriStack
Alcohol and Metronidazole, contraindicated.
Metronidazole inhibits acetaldehyde dehydrogenase, and concurrent alcohol can trigger a disulfiram-like reaction including flushing, severe nausea, vomiting, headache, tachycardia, and chest pain. Although recent reviews have debated whether the reaction occurs in all patients, multiple case reports describe serious reactions and the manufacturer warning remains in place. Severe cases have caused hypotension and even death.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Alcohol and Metronidazole
- Pair type
- Contraindicated
- Evidence (highest tier)
- Strong
- Source citations
- 3 sources
- Stack Score effect
- −25 to your Stack Score (per scored contraindication row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Contraindicated · Strong evidence
Contraindicated
What is happening. Metronidazole inhibits acetaldehyde dehydrogenase, and concurrent alcohol can trigger a disulfiram-like reaction including flushing, severe nausea, vomiting, headache, tachycardia, and chest pain. Although recent reviews have debated whether the reaction occurs in all patients, multiple case reports describe serious reactions and the manufacturer warning remains in place. Severe cases have caused hypotension and even death.
Mechanism. Metronidazole inhibits hepatic and intestinal acetaldehyde dehydrogenase (ALDH), causing acetaldehyde accumulation when ethanol is consumed. Some animal data also suggest intracolonic acetaldehyde accumulation via altered gut flora.
Recommendation. Do not drink alcohol while taking metronidazole. Wait at least 3 days (72 hours) after your last dose before consuming alcohol, including alcohol in mouthwashes, cough syrups, and food preparations.
Sources (3)
- Williams CS, Woodcock KR. Do ethanol and metronidazole interact to produce a disulfiram-like reaction? Ann Pharmacother. 2000;34(2):255-257. PMID 10676835
- Tillonen J, Väkeväinen S, Salaspuro V, et al. Metronidazole increases intracolonic but not peripheral blood acetaldehyde in chronic ethanol-treated rats. Alcohol Clin Exp Res. 2000;24(4):570-5. PMID 10798595
- Feldman R, Jaszczenski R. Can Metronidazole Cause a Disulfiram-Like Reaction? A Case-Control Study Propensity Matched by Age, Sex, and Ethanol Concentration. WMJ. 2023;122(3):171-177. PMID 37494646
Stack Score
How this pair moves the number.
Effect on the composite score
If both Alcohol and Metronidazole are in the same stack, this pair applies −25 to your Stack Score (per scored contraindication row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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