What kind of interaction is it?

Caution: an interaction that may reduce efficacy or raise side-effect risk and warrants monitoring.

Is this interaction backed by published research?

Yes. NutriStack lists 1 citation row for the Rifampin + St. John's Wort pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Supplement × Prescription·a caution·Moderate evidence

Rifampin + St. John's Wort

Q: Can I take Rifampin and St. John's Wort together?

Possibly, but with caution. Rifampin and St. John's Wort have a documented caution-tier interaction. St. John's Wort and rifampin are both strong induction concerns for drug-metabolizing enzymes and transporters; the main danger is failure of other concomitant drugs, not loss of rifampin exposure.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored caution row.

Caution Moderate evidence

St. John's Wort and rifampin are both strong induction concerns for drug-metabolizing enzymes and transporters; the main danger is failure of other concomitant drugs, not loss of rifampin exposure.

Supplement × Prescription

Open the interaction checker → Read the methodology

From the database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, and the recommendation.

Substances

Rifampin and St. John's Wort

Pair type

Caution

Evidence

Moderate

Source citations

Scope

Supplement × Prescription

Last verified

June 4, 2026

CautionModerate evidence

What is happening. St. John's Wort and rifampin are both strong induction concerns for drug-metabolizing enzymes and transporters; the main danger is failure of other concomitant drugs, not loss of rifampin exposure.

Mechanism. Both agents can induce CYP3A4 and P-glycoprotein pathways, creating additive risk for reduced exposure of susceptible third-party medications.

Recommendation. Avoid combining unless the full medication list has been reviewed; monitor or adjust affected concomitant drugs such as anticoagulants, antiretrovirals, transplant drugs, hormonal contraceptives, and azole antifungals.

Stack Score

How it moves the number.

Effect on the composite score

If both Rifampin and St. John's Wort are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).

The full algorithm, the clamping rules, and four worked stacks are at /methodology/stack-score.

Sources

Sources, by evidence tier.

Every claim on this page is cited. PMIDs link straight to PubMed.

Reference material

1Izzo AA, Ernst E. Interactions between herbal medicines and prescribed drugs: an updated systematic review. Drugs. 2009.Needs sourceNo link

Check your full routine

One pair was the worked example.

Drop your supplements and prescriptions into NutriStack and it runs every pair at once: every interaction, synergy, timing rule, and contraindication, each linked to its primary source.

Open the interaction checker → Browse the research index