NutriStack
Fluoxetine and St. John's Wort, contraindicated.
Combining fluoxetine with St. John's Wort creates a high risk of serotonin syndrome. Fluoxetine has a long half-life (including its active metabolite norfluoxetine), meaning the risk persists for weeks after discontinuation. Multiple case reports document this dangerous interaction.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
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
- Fluoxetine and St. John's Wort
- Pair type
- Contraindicated
- Evidence (highest tier)
- Strong
- Source citations
- 1 source
- 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. Combining fluoxetine with St. John's Wort creates a high risk of serotonin syndrome. Fluoxetine has a long half-life (including its active metabolite norfluoxetine), meaning the risk persists for weeks after discontinuation. Multiple case reports document this dangerous interaction.
Mechanism. Fluoxetine and its active metabolite norfluoxetine potently inhibit SERT, with a combined half-life of 4-16 days. St. John's Wort's additional serotonin reuptake inhibition (via hyperforin) and potential MAO inhibition creates dangerous serotonergic excess.
Recommendation. Do not take St. John's Wort with fluoxetine. Due to fluoxetine's long half-life, wait at least 5 weeks after stopping fluoxetine before starting St. John's Wort. Seek immediate medical attention for symptoms of serotonin syndrome.
Sources (1)
Stack Score
How this pair moves the number.
Effect on the composite score
If both Fluoxetine and St. John's Wort 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.
Check your full routine
One pair was the worked example. NutriStack runs every pair in your stack at once.
Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.