The short answer
Avoid adding oral comfrey while taking gefitinib without the cancer team’s review. Both the supplement evidence and gefitinib’s product information raise liver concerns, although an exact combined risk has not been measured.
What this answer covers
Oral comfrey preparations with oral gefitinib. Swallowed pyrrolizidine-alkaloid exposure is distinct from restricted topical comfrey use.
- Supplement or preparation
- Symphytum officinale
- Medication ingredient
- gefitinib
Check the exact treatment
This review concerns oral gefitinib tablets used for selected EGFR-mutated lung cancers. The prescribed tablet and dosing plan matter. Follow the cancer team’s instructions; food, acid reducers and supplements should be reviewed together.
What is known about the supplement
An original case linked swallowed comfrey to hepatic veno-occlusive disease. Comfrey can contain pyrrolizidine alkaloids that are toxic to the liver when swallowed. The case does not measure an interaction with gefitinib or the risk from every preparation.
Keep preparation and route separate
The assessment of carefully specified short-term comfrey products applied to the skin is a different question from oral ingestion. Do not assume that evidence about swallowed comfrey proves the same risk for every cream, or that an external-use product can safely be swallowed.
Follow the liver-monitoring plan
Gefitinib requires periodic liver tests. Tell the team about supplements already used and promptly report yellowing eyes or skin, dark urine, or persistent nausea and loss of appetite. A few hours between doses has not been shown to prevent liver injury, and you should not adjust cancer treatment yourself.
Evidence and practical considerations
Side effects & toxicity
Supplement-specific liver injury supports a conditional precaution during a medicine with its own hepatotoxicity warning.
- Exact scope
- Oral comfrey preparations with oral gefitinib. Swallowed pyrrolizidine-alkaloid exposure is distinct from restricted topical comfrey use. with RxNorm 328134 IN gefitinib. Current exact oral product: Gefitinib oral tablets. Salt/formulation named explicitly; no transfer to unrelated drugs or routes.
- Medication form and route
- Oral
What remains uncertain
- No exact comfrey-gefitinib clinical interaction study. Conditional liver-risk precaution based on separate evidence; no measured additive incidence or validated spacing.
Factors that may matter: Exact oral formulation and supplement preparation; Drug exposure versus clinical outcomes; Dose, duration and other medicines; Individual monitoring plan.
Read the supporting source summaries
Source 1: Current original prescribing information
dailymed.nlm.nih.gov · Source check Sep 10, 2026
Population: Patients prescribed the exact oral formulation.
Six-hour antacid separation; CYP3A induction can lower exposure; periodic liver monitoring.
How this applies: RxNorm 328134 IN gefitinib. Current exact oral product: Gefitinib oral tablets. Salt/formulation named explicitly; no transfer to unrelated drugs or routes.
Exact current oral product source, not a clinical trial of every supplement. Formulation, dose, population and mechanism remain explicit.
Source 2: Original clinical research
pubmed.ncbi.nlm.nih.gov · Source check Sep 10, 2026
Population: Patient with reported comfrey ingestion and liver injury.
Temporal and pathological findings suggested hepatic veno-occlusive disease associated with ingestion.
How this applies: Exact reported preparation, population and endpoints; transfer to gefitinib explicitly limited.
Abstract-only case, no gefitinib combination or quantified incidence; not topical comfrey.
Source 3: Original official botanical guidance
ema.europa.eu · Source check Sep 10, 2026
Population: Oral versus topical preparations.
Alkaloids can be hepatotoxic when swallowed; assessed short-term skin use differs.
How this applies: Oral preparation risk bridge.
Not an exact gefitinib study; no transfer from oral poisoning to all topical products.
Source 4: Medication terminology
rxnav.nlm.nih.gov · Source check Sep 10, 2026
Population: Terminology.
gefitinib is IN.
How this applies: Exact ingredient.
Not clinical evidence.
Research assessment: · Open full citations ↗
Review and change history
- Publication status
- Published research summary
- Clinical review
- Not yet recorded
| Date | Update |
|---|---|
| Research summary published | |
| Article prepared | |
| Sources checked and article drafted. |
Article revision: 942623a8770f981e
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.