Evidence Explorer / Evidence record
BOTANICALS & NATURAL PRODUCTS
St. John’s wort and irinotecan
Documented interaction
Exposure to SN-38, irinotecan’s active metabolite, fell by 42% with St. John’s wort in five patients.
MS-N002 · Sources checked October 11, 2026 · Treatment-interaction safety
What was studied?
People and setting: People receiving irinotecan
Evidence basis: Small randomized crossover pharmacokinetic study
What can we conclude?
This measured drug exposure, not cancer survival; nevertheless, reduced active-drug exposure is a clinically important concern.
Safety and practical context
Patients on irinotecan should avoid St. John’s wort and discuss any current use with the oncology pharmacist.
Questions for the care team
- Does this evidence apply to my cancer, treatment and goal?
- Does the exact preparation or delivery method match the study?
- What benefit is plausible, what could go wrong, and what care must continue?
Sources
Connected reviews
Learn how to judge a study · Return to the evidence map
This is a concise evidence brief, not an exhaustive systematic review or a personal treatment recommendation. Evidence labels describe the named use; they are not formal GRADE ratings. A missing harm report does not establish safety.
