The short answer
St John’s wort can increase serotonin-syndrome risk with lithium citrate. The lithium oral solution label explicitly names the herb, although it does not quantify the risk for each product.
What this answer covers
Oral Hypericum perforatum with lithium citrate oral solution; other serotonergic medicines and product composition matter.
- Supplement or preparation
- Hypericum perforatum
- Medication ingredient
- lithium citrate
A named label warning
The lithium oral solution label lists St John’s wort among serotonergic agents that increase serotonin-syndrome risk. This directly supports a precaution for the combination without relying on an interaction reported with another lithium salt.
This is a serotonin effect
The warning concerns excessive serotonin activity. It does not establish that the herb raises lithium absorption or blood levels. Lithium is not metabolized and is cleared mainly through the kidneys, so a general CYP-enzyme explanation is insufficient.
Recognize a concerning pattern
Serotonin syndrome can involve agitation or confusion together with fever, sweating, rapid heartbeat, muscle rigidity, twitching or exaggerated reflexes, sometimes with vomiting or diarrhea. A concerning combination of these symptoms needs urgent medical assessment.
Review before starting or stopping
Discuss St John’s wort and all other mood or sleep products with the prescriber before changing use. The label calls for informing and monitoring patients when combined serotonergic treatment is warranted. It does not establish a protective spacing interval or a self-directed lithium dose change.
Evidence and practical considerations
Side effects & toxicity
Exact lithium oral solution label explicitly names St John’s wort as increasing serotonin-syndrome risk; no product-specific incidence is supplied.
- Exact scope
- Oral Hypericum perforatum with lithium citrate oral solution; other serotonergic medicines and product composition matter. with Lithium citrate oral solution, exact RxCUI 52105; current NLM IN. Carbonate evidence is indirect through lithium ion where stated.
- Medication form and route
- oral lithium citrate; oral supplement
What remains uncertain
- Source-specific identity, preparation and endpoint limitations apply; no unstudied dose conversion.
Factors that may matter: Exact preparation; Amount and changes in use; Kidney function; Other medicines.
Read the supporting source summaries
Source 1: current product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: People prescribed lithium oral solution.
Lithium is eliminated mainly in urine. Sodium depletion can reduce clearance and raise levels; xanthines and alkalinizing agents can increase urinary excretion and lower levels. Serotonergic agents, explicitly including St John’s wort, increase serotonin-syndrome risk.
How this applies: Only the stated identity, preparation, route and endpoints; limitations also govern extrapolation to the exact pair.
Lithium active-moiety bridge supports renal pharmacology across salts but not identical formulation kinetics, dose equivalence for self-use or quantified effects of every herb.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Prepared exact-pair article preserving salt, botanical and evidence limitations. | |
| Research summary published |
Article revision: 2a6252d8fa75acbf
This guide brings together the evidence records used by our interaction checker. Each finding retains its own preparation limits, research date, and source summaries.
Full citations require verification. Reading this answer and the source summaries does not.
Taking other supplements or medications?
Use the checker to explore your other combinations. Ask a pharmacist to review the exact products, amounts and medical conditions in your complete list.
Open the interaction checkerInformation, not medical advice. Do not change prescribed treatment based on this guide.