The short answer
Oral comfrey carries a liver-toxicity concern and should be reviewed with your cancer team. The added risk with adagrasib is unknown, and skin products require a separate formulation assessment.
What this answer covers
Symphytum officinale oral products with oral adagrasib, distinguished from short-term skin use of specified low-pyrrolizidine-alkaloid root medicines. Historical common-name comfrey leaf cases do not establish exact species identity.
- Supplement or preparation
- Symphytum officinale
- Medication ingredient
- adagrasib
Oral comfrey has a liver-toxicity concern
The European assessment identifies liver-toxic pyrrolizidine alkaloids in Symphytum officinale root when taken by mouth. An older report described fatal liver disease after comfrey leaf ingestion, although the inspected abstract did not authenticate the species. Avoid swallowing comfrey products and discuss existing use with your cancer team.
The exact combination remains unmeasured
Krazati can independently cause liver injury. That makes an additional oral product with known liver toxicity a poor choice for unsupervised use, but does not establish how much taking both increases risk. The case report predates adagrasib and cannot supply a combination event rate.
Skin products are a different exposure
The European assessment of short-term topical comfrey concerns specified root preparations with controlled alkaloid content. It does not make every cream, homemade preparation or leaf product equivalent, and it does not test co-use with adagrasib. Show the pharmacist the full product label and explain how you use it.
Keep liver monitoring and report changes
Follow the cancer team’s liver-test plan. The Krazati label recommends tests before treatment, monthly for the first three months and as clinically indicated. Report jaundice, dark urine or persistent upper-abdominal discomfort promptly, and do not use dose spacing as a presumed way to prevent liver injury.
Evidence and practical considerations
Side effects & toxicity
The added liver-injury risk specifically from Symphytum officinale with adagrasib has not been measured.
- Exact scope
- Symphytum officinale oral products with oral adagrasib, distinguished from short-term skin use of specified low-pyrrolizidine-alkaloid root medicines. Historical common-name comfrey leaf cases do not establish exact species identity. with Exact adagrasib RxCUI 2625882 IN, confirmed by current RxNorm properties. Oral Krazati tablets; the August 2026 U.S. label covers single-agent treatment of specified previously treated KRAS G12C-mutated NSCLC. Older cetuximab combination cohorts and regional label instructions are not interchangeable.
- Medication form and route
- Oral
What remains uncertain
- Historical leaf case has uncertain species and no adagrasib. Exact-species root guidance concerns intrinsic oral toxicity and a separate topical-use assessment.
Factors that may matter: Exact preparation and dose; Treatment phase and duration; Liver function; Electrolyte results and GI symptoms; Other medicines.
Read the supporting source summaries
Source 1: Current U.S. prescribing information
bms.com · Source check Sep 10, 2026
Population: Adults with specified previously treated KRAS G12C-mutated locally advanced or metastatic non-small cell lung cancer.
Warns about GI toxicity, QT prolongation and hepatotoxicity. Monitor/correct electrolytes, particularly potassium and magnesium, and monitor liver tests. Strong CYP3A inducers lower exposure. Avoid strong CYP3A inhibitors until steady state, approximately eight days. High-fat meal did not meaningfully change exposure; tablets may be taken with or without food.
How this applies: Exact current U.S. guidance; newer than the retained March 2026 DailyMed version. Exact adagrasib RxCUI 2625882 IN, confirmed by current RxNorm properties. Oral Krazati tablets; the August 2026 U.S. label covers single-agent treatment of specified previously treated KRAS G12C-mutated NSCLC. Older cetuximab combination cohorts and regional label instructions are not interchangeable.
Not direct evidence of each botanical combination. Strong-inhibitor effects after a single dose differ from steady-state model predictions. Effects of adagrasib on other CYP substrates are a separate direction. No universal supplement prescription.
Source 2: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: One 23-year-old man with fatal hepatic veno-occlusive disease.
Temporal association and pathological findings suggested comfrey-associated liver injury.
How this applies: Adjacent oral comfrey leaf evidence, with species uncertainty retained.
Abstract-only case, no adagrasib; botanical species and pyrrolizidine-alkaloid dose not authenticated in the inspected abstract. Cannot assign the case specifically to S. officinale or to topical root products.
Source 3: Regulatory herbal assessment summary
ema.europa.eu · Source check Sep 10, 2026
Population: Users of specified Symphytum officinale root medicines for topical use.
States that comfrey root contains pyrrolizidine alkaloids toxic to the liver when taken by mouth. Its assessment of short-term skin use is a different route.
How this applies: Exact S. officinale root identity and oral-versus-topical toxicity boundary.
Regulatory summary, not an adagrasib trial. Does not authenticate species in historical common-name case reports or establish safety for every topical preparation.
Source 4: Authoritative medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Medication terminology.
Identifies adagrasib as IN.
How this applies: Exact identity confirmation.
Not clinical interaction evidence.
Research assessment: · Open full citations ↗
Side effects & toxicity
Pyrrolizidine-alkaloid-containing comfrey should not be taken by mouth without clinical review, particularly during a liver-monitored cancer treatment.
- Exact scope
- Symphytum officinale oral products with oral adagrasib, distinguished from short-term skin use of specified low-pyrrolizidine-alkaloid root medicines. Historical common-name comfrey leaf cases do not establish exact species identity. with Exact adagrasib RxCUI 2625882 IN, confirmed by current RxNorm properties. Oral Krazati tablets; the August 2026 U.S. label covers single-agent treatment of specified previously treated KRAS G12C-mutated NSCLC. Older cetuximab combination cohorts and regional label instructions are not interchangeable.
- Medication form and route
- Oral
What remains uncertain
- Precaution based on known oral alkaloid toxicity, not an observed additive interaction. Topical products differ, but their safety with adagrasib has not been established by these sources.
Factors that may matter: Exact preparation and dose; Treatment phase and duration; Liver function; Electrolyte results and GI symptoms; Other medicines.
Read the supporting source summaries
Source 1: Current U.S. prescribing information
bms.com · Source check Sep 10, 2026
Population: Adults with specified previously treated KRAS G12C-mutated locally advanced or metastatic non-small cell lung cancer.
Warns about GI toxicity, QT prolongation and hepatotoxicity. Monitor/correct electrolytes, particularly potassium and magnesium, and monitor liver tests. Strong CYP3A inducers lower exposure. Avoid strong CYP3A inhibitors until steady state, approximately eight days. High-fat meal did not meaningfully change exposure; tablets may be taken with or without food.
How this applies: Exact current U.S. guidance; newer than the retained March 2026 DailyMed version. Exact adagrasib RxCUI 2625882 IN, confirmed by current RxNorm properties. Oral Krazati tablets; the August 2026 U.S. label covers single-agent treatment of specified previously treated KRAS G12C-mutated NSCLC. Older cetuximab combination cohorts and regional label instructions are not interchangeable.
Not direct evidence of each botanical combination. Strong-inhibitor effects after a single dose differ from steady-state model predictions. Effects of adagrasib on other CYP substrates are a separate direction. No universal supplement prescription.
Source 2: Regulatory herbal assessment summary
ema.europa.eu · Source check Sep 10, 2026
Population: Users of specified Symphytum officinale root medicines for topical use.
States that comfrey root contains pyrrolizidine alkaloids toxic to the liver when taken by mouth. Its assessment of short-term skin use is a different route.
How this applies: Exact S. officinale root identity and oral-versus-topical toxicity boundary.
Regulatory summary, not an adagrasib trial. Does not authenticate species in historical common-name case reports or establish safety for every topical preparation.
Source 3: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: One 23-year-old man with fatal hepatic veno-occlusive disease.
Temporal association and pathological findings suggested comfrey-associated liver injury.
How this applies: Adjacent oral comfrey leaf evidence, with species uncertainty retained.
Abstract-only case, no adagrasib; botanical species and pyrrolizidine-alkaloid dose not authenticated in the inspected abstract. Cannot assign the case specifically to S. officinale or to topical root products.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Article prepared | |
| Sources checked and article drafted. | |
| Research summary published |
Article revision: 33f705cc708143ef
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.