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Drugs and Lactation Database (LactMed®) [Internet]. Bethesda (MD): National Institute of Child Health and Human Development; 2006-.

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Drugs and Lactation Database (LactMed®) [Internet].

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Comfrey

Last Revision: May 17, 2021.

Estimated reading time: 2 minutes

CASRN: 84696-05-9

Drug Levels and Effects

Summary of Use during Lactation

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.

Drug Levels

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.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

References

1.
Low Dog T. The use of botanicals during pregnancy and lactation. Altern Ther Health Med. 2009;15:54–8. [PubMed: 19161049]
2.
Petrie KA, Peck MR. Alternative medicine in maternity care. Prim Care. 2000;27:117–36. [PubMed: 10739460]
3.
Kopec K. Herbal medications and breastfeeding. J Hum Lact. 1999;15:157–61. [PubMed: 10578793]
4.
Allaire AD, Moos MK, Wells SR. Complementary and alternative medicine in pregnancy: A survey of North Carolina certified nurse-midwives. Obstet Gynecol. 2000;95:19–23. [PubMed: 10636495]
5.
Dennehy C, Tsourounis C, Bui L, et al. The use of herbs by California midwives. J Obstet Gynecol Neonatal Nurs. 2010;39:684–93. [PubMed: 21044150]
6.
Yarnell E. Botanical medicine in pregnancy and lactation. Altern Complement Ther. 1997;3(April):93–100.
7.
Fleiss P. Herbal remedies for the breastfeeding mother. Mothering 1988;Summer:68-71.
8.
Panter KE, James LF. Natural plant toxicants in milk: A review. J Anim Sci. 1990;68:892–904. [PubMed: 2180885]
9.
Winship KA. Toxicity of comfrey. Adverse Drug React Toxicol Rev. 1991;10:47–59. [PubMed: 1878443]
10.
Howard CR, Lawrence RA. Drugs and breastfeeding. Clin Perinatol. 1999;26:447–78. [PubMed: 10394496]

Substance Identification

Substance Name

Comfrey

CAS Registry Number

84696-05-9

Drug Class

Breast Feeding

Lactation

Anti-Inflammatory Agents

Complementary Therapies

Phytotherapy

Plants, Medicinal

Disclaimer: Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

Copyright Notice

Attribution Statement: LactMed is a registered trademark of the U.S. Department of Health and Human Services.

Bookshelf ID: NBK501773PMID: 30000832

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