Summary of Use during Lactation

Blessed thistle (Cnicus benedictus, Carduus benedictus, Cardui benedicti) contains sesquiterpene lactones, triterpenoids, lignans, tannins, essential oils, flavonoids, and polyenes. Blessed thistle is a purported galactogogue,[1-6] and is included in some proprietary mixtures promoted to increase milk supply; however, no scientifically valid clinical trials support this use. Galactogogues should never replace evaluation and counseling on modifiable factors that affect milk production.[7,8] Blessed thistle is "generally recognized as safe" (GRAS) as a flavoring in alcoholic beverages (e.g., Benedictine) by the U.S. Food and Drug Administration. Because it is a member of the ragweed family, allergy is a concern and high doses reportedly cause stomach cramps, nausea and vomiting. Elevated liver enzymes occurred in a woman taking Mother's Milk Tea, which contains blessed thistle and other ingredients.[9]

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

A small manufacturer-sponsored, double-blind, randomized study compared Mother's Milk tea (Traditional Medicinals, Sebastopol, CA) to lemon verbena tea in exclusively breastfeeding mothers with milk insufficiency. Each Mother's Milk tea bag contained 35 mg of blessed thistle herb as well as several other herbs. Mothers were instructed to drink 3 to 5 cups of tea daily. No differences were seen between groups in infant digestive, respiratory, dermatological, and other maternal-reported adverse events. No differences were seen in the growth parameters of the breastfed infants between the two groups.[10]

Effects on Lactation and Breastmilk

In a survey of nursing mothers in Australia, 98 mothers were taking blessed thistle as a galactogogue. On average, mothers rated blessed thistle being between “slightly effective” and “moderately effective” on a Likert scale. Eight percent of mothers taking blessed thistle reported experiencing adverse reactions, most commonly nausea, stomach cramps, dry mouth and fatigue.[11]

References

1.

Howard CR, Lawrence RA. Drugs and breastfeeding. Clin Perinatol. 1999;26:447–78. [PubMed: 10394496]

2.

Petrie KA, Peck MR. Alternative medicine in maternity care. Prim Care. 2000;27:117–36. [PubMed: 10739460]

3.

Westfall RE. Galactagogue herbs: A qualitative study and review. Can J Midwifery Res Practice. 2003;2:22–7.

4.

Low Dog T. The use of botanicals during pregnancy and lactation. Altern Ther Health Med. 2009;15:54–8. [PubMed: 19161049]

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.

Abascal K, Yarnell E. Botanical galactagogues. Altern Complement Ther. 2008;14:288–94. [CrossRef]

7.

Brodribb W. ABM Clinical Protocol #9. Use of galactogogues in initiating or augmenting maternal milk production, second revision 2018. Breastfeed Med. 2018;13:307–14. [PubMed: 29902083]

8.

Breastfeeding challenges: ACOG Committee Opinion, Number 820. Obstet Gynecol. 2021;137:e42–e53. [PubMed: 33481531]

9.

Silverman AL, Kumar A, Borum ML. Re: "Herbal use during breastfeeding" by Anderson (Breastfeed Med 2017;12(9):507-509). Breastfeed Med. 2018;13:301. [PubMed: 29757695]

10.

Wagner CL, Boan AD, Marzolf A, et al. The safety of Mother's Milk(R) Tea: Results of a randomized double-blind, controlled study in fully breastfeeding mothers and their infants. J Hum Lact. 2019;35:248–60. [PubMed: 30005170]

11.

McBride GM, Stevenson R, Zizzo G, et al. Use and experiences of galactagogues while breastfeeding among Australian women. PLoS One. 2021;16:e0254049. [PMC free article: PMC8248610] [PubMed: 34197558]

Substance Name

Blessed Thistle

CAS Registry Number

201530-41-8

Scientific Name

Cnicus benedictus

Drug Class

Breast Feeding

Lactation

Complementary Therapies

Galactogogues

Phytotherapy

Plants, Medicinal