The short answer
Avoid self-starting oral chaparral while taking valproate and review any current use with your prescriber. Chaparral has been linked to severe liver injury, and valproate also has a liver warning. The added risk of the combination is unknown.
What this answer covers
Oral chaparral reported as Larrea tridentata; other species, purified constituents and topical preparations are outside this evidence.
- Supplement or preparation
- Larrea tridentata
- Medication ingredient
- valproate
The chaparral evidence
A review of 18 reports submitted to the FDA identified liver injury in 13. Some progressed to cirrhosis or liver transplantation. These reports establish a serious concern but do not tell us how often injury occurs among all users.
Why valproate warrants extra review
Valproate has its own potentially serious liver effects. A second product associated with liver injury complicates decisions about new symptoms or abnormal tests. This supports a precaution, while the combination itself remains unstudied in the cited evidence.
A timing change is not a proven safeguard
The reports do not establish a safe chaparral dose or an interval that prevents liver injury. Advice about oral chaparral should not be automatically transferred to another species or a skin preparation.
Review use and symptoms with your clinician
Bring the product label and your dose and duration of use to your prescriber. Valproate requires liver monitoring, especially early in treatment. Seek prompt medical assessment for new loss of appetite, vomiting, marked weakness or unusual lethargy. Do not abruptly stop an anticonvulsant prescribed for epilepsy; medication decisions need your treating team.
Evidence and practical considerations
Side effects & toxicity
Separate liver-injury concerns support avoiding unsupervised oral chaparral use during valproate treatment; added interaction risk has not been measured.
- Exact scope
- Oral chaparral reported as Larrea tridentata; other species, purified constituents and topical preparations are outside this evidence. with Oral valproate active moiety; label evidence is from oral valproic acid capsules, with Depakote exposure identified separately where relevant.
- Medication form and route
- oral valproate; supplement route as specified in source and scope
- Timing or duration
- No safe co-use duration or protective spacing interval established.
What remains uncertain
- Spontaneous reports provide no incidence estimate or direct valproate comparison.
Factors that may matter: existing liver disease; uncertain product composition; first six months of valproate treatment.
Read the supporting source summaries
Source 1: current oral product label
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed oral valproic acid capsules.
Label warns of potentially fatal liver injury, especially during the first six months, and thrombocytopenia/coagulation abnormalities. It recommends baseline and follow-up liver and blood assessments. P450 oxidation is a minor metabolic pathway. Aspirin increased free valproate fraction in six pediatric patients; the study is aspirin-specific.
How this applies: Medication risk and identity context for RxCUI 40254 valproate; oral active-moiety bridge only.
Not a study of any of these botanical combinations. Active-moiety identity does not establish interchangeable doses, release kinetics or routes. Aspirin results do not establish salicin or methyl salicylate effects.
Source 2: FDA adverse-event case series
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: 18 reports to FDA during 1992-1994.
13 reports had hepatotoxicity, four progressed to cirrhosis and two involved liver transplantation; symptoms began 3-52 weeks after ingestion.
How this applies: Separate oral chaparral liver-injury concern, not measured added interaction risk.
Spontaneous reports cannot estimate incidence; no valproate-specific exposure or comparison in the abstract.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Original sources checked and exact-pair evidence package prepared; no clinical review asserted. | |
| Research summary published |
Article revision: 84241be81f846493
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.