Is St. John's Wort Safe with Acetaminophen?
Free · No account · based on published sources including NIH ODS, FDA drug labels, and peer-reviewed literature
Avoid combining St. John's Wort with Acetaminophen — St. John's Wort speeds up the liver enzyme (CYP1A2) that breaks down Acetaminophen, potentially reducing its effectiveness. Consult your doctor.
Why this interaction occurs
Induces hepatic CYP1A2. Result: decreased drug levels. May reduce efficacy of CYP1A2 substrates
Evidence
Evidence level: moderate.
Reported safety data
The FDA’s adverse event reporting system (FAERS) has received 487,910 reports mentioning Acetaminophen. This reflects reported cases involving the medication in general — not confirmed causation, and not specific to the Acetaminophen + supplement combination on this page.
FAERS reports are voluntary and cannot prove that a drug caused an event. Do not use report counts to assess the safety of this specific drug-supplement pair.
Frequently asked questions
Related interactions
All St. John's Wort interactions → · All Acetaminophen interactions →
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Educational only — not medical advice.
Always confirm with your doctor or pharmacist.