Is Comfrey safe while breastfeeding?
Here is what LactMed, the Drugs and Lactation Database published by the U.S. National Institute of Child Health and Human Development (NICHD), reports about Comfrey. The text below is quoted from that source — it is not our own verdict.
Summary of use during breastfeeding
Comfrey (Symphytum officinalis) herb and leaf contains allantoin and rosmarinic acid; comfrey also contains pyrrolizidine alkaloids. Comfrey preparations have been used topically for pain following episiotomy and cracked, painful nipples, either as aqueous preparations or in creams and ointments.[1-7] Scientific evidence of effectiveness for these indications is minimal. The pyrrolizidine alkaloids in comfrey can cause severe liver damage, liver cancer, mutagenicity, and even death.[8,9] For this reason, the U.S. Food and Drug Administration has banned the sale of oral comfrey products in the United States. Furthermore, most sources consider topical use of comfrey during breastfeeding to be contraindicated.[1,10] If it is used on the skin, it should only be applied to intact skin away from the breast on the smallest area of skin possible, and for a limited duration. It is particularly important to ensure that the infant not come into direct contact with the areas of skin that have been treated, because ingestion may cause severe liver damage.
Dietary supplements do not require extensive pre-marketing approval from the U.S. Food and Drug Administration. Manufacturers are responsible to ensure the safety, but do not need to prove the safety and effectiveness of dietary supplements before they are marketed. Dietary supplements may contain multiple ingredients, and differences are often found between labeled and actual ingredients or their amounts. A manufacturer may contract with an independent organization to verify the quality of a product or its ingredients, but that does not certify the safety or effectiveness of a product. Because of the above issues, clinical testing results on one product may not be applicable to other products. More detailed information about dietary supplements is available elsewhere on the LactMed Web site.
Effects on the breastfed infant
Relevant published information was not found as of the revision date.
Effects on milk supply
Relevant published information was not found as of the revision date.
Levels in milk
Maternal Levels. Relevant published information was not found as of the revision date.
Infant Levels. Relevant published information was not found as of the revision date.
“No published information” means the studies do not exist yet — not that Comfrey is known to be harmful, and not that it is known to be safe. Your prescriber or pharmacist can weigh your baby's age and whether a better-studied alternative would do the same job. Worth asking before stopping a medicine you need.
Source: Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Comfrey” (LM865). LactMed on NCBI Bookshelf. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
Educational summary of an authoritative source — not medical advice. Never start, stop, or change a medicine while breastfeeding without confirming with your doctor.