Is it dangerous to use certain herbals, vitamins, or other dietary supplements when breastfeeding?

Answer:

Certain herbals, high dose vitamins, and other dietary supplements can be dangerous to breastfed babies through breast milk. Below is a list of some of the herbs and supplements that should be avoided during breastfeeding (use the links for more information). As there may be other supplements that are contraindicated during breastfeeding, always consult with your physician before taking any supplement. Of course, certain prescription medications taken by mothers may also be dangerous to breastfed babies.

Supplements and herbs to avoid when breastfeeding:

Aloe latex

Ashwagandha

Berberine/goldenseal (berberine is a compound found in goldenseal)

Bilberry

Black cohosh

Butterbur — Contains compounds that may cause liver damage (Chojkier, J Hepatol 2003)

Dong quai (Angelica sinensis) (National Library of Medicine 2018)

Echinacea

Feverfew (Tanacetum parthenium) (Amir, Aust Fam Physician 2011)

Gingko biloba

Kava kava — Possible central nervous depression and/or skin discoloration in the breastfed baby; rarely, it may cause allergic reactions and sedation with high doses (Romm, 2010; NIH, 2020)

Kelp supplements

Licorice (National Library of Medicine 2018)

Melatonin

Quercetin

Rhodiola (Rhodiola rosea)

Soy Isoflavones

Turmeric/curcumin

Vinpocetine

In addition, some experts advise avoiding the following herbs due to a lack of evidence of safety and efficacy:

Devil's claw (Harpagophytum procumbens)

Feverfew (Tanacetum parthenium)

Hawthorn (Crataegus oxycantha)

Horse chestnut (Aesculus hippocastanum)

Marigold (Calendula officinalis).

Supplements and herbs to use with caution:

Aloe — If used topically, wash off before breastfeeding as it may cause diarrhea in infants

Fenugreek — Although traditionally used to promote milk production, side effects such as maple syrup smell emitted from the mother's body, gassiness in the baby, or breast milk oversupply have been reported (National Library of Medicine 2020)

Green tea

Possibly helpful:

Probiotics — Certain probiotic strains may be helpful for women with mastitis

In addition to the resources on ConsumerLab.com, an excellent article on the subject of medications (including supplements) and breastfeeding is found at https://www.japha.org/article/S1544-3191(15)30430-1/fulltext.