St. John's Wort

Drug Levels and Effects:

Summary of Use during Lactation:

St. John's wort (</span>Hypericumperforatum) contains hypericin and hyperforin. It is often recommended by midwives for postpartum depression.[1][2] Both hypericin and hyperforin are poorly excreted into breastmilk; no other components have been measured in milk. One study found a slightly increased frequency of colic, drowsiness and lethargy among breastfed infants whose mothers were taking St. John's wort, but none of the effects were severe or required treatment. Most reports have related to breastfeeding older infants, rather than during the first 2 months postpartum when infants are more susceptible to adverse reactions. Conflicting information exists on whether St. John's wort can reduce serum prolactin levels or the maternal milk supply. St. John's wort is known to adversely interact with many drugs and occasionally cause phototoxicity. Labeling of commercially available products in the United States is often deficient with respect to these known safety issues.[3] Because there is little published experience with St. John's wort during breastfeeding, an alternate drug may be preferred, especially while nursing a newborn or preterm infant.

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Drug Levels:

Most studies have used Jarsin brand (Lichtwer Pharma AG, Berlin, Germany, marketed as Kira brand in the United States) of St. John's wort which is an 80% methanolic dry extract that contains 0.21% hypericin and 2.5% hyperforin.[4]

Maternal Levels.

A postpartum woman with depression began taking St. John's wort (Jarsin brand) 300 mg 3 times daily starting at 5 months postpartum. At 7 months postpartum, 8 breastmilk samples (4 foremilk and 4 hindmilk) were taken over an 18-hour period. Hypericin was undetectable (<0.2 mcg/L) in all samples. In foremilk, hyperforin was undetectable (<0.5 mcg/L) in 2 samples and was 0.58 and 1.01 mcg/L in 2 others. In hindmilk, hyperforin was found in all samples with an average concentration of 5.77 mcg/L. The lowest level of 0.86 mcg/L was at about 2.25 hours after the morning dose, and the highest level of 18.2 mcg/L was about 1.75 hours before the morning dose and 10 hours after the previous nursing.[5]

In a second study by the same group, 5 women who were 10 to 22 weeks postpartum and had been taking St. John's wort (Jarsin brand) 300 mg 3 times daily for at least 4 weeks provided milk samples over an 18-hour period. From a total of 36 fore- and hindmilk samples, the overall average hyperforin concentrations in foremilk and hindmilk were both 3.5 mcg/L (range 0.1 to 31.5 mcg/L). Hypericin was not measured. The average infant dosage was 1.5% (range 0.9 to 2.5%) of the maternal weight-adjusted dosage.[6]

Infant Levels.

A postpartum woman with depression began taking St. John's wort (Jarsin brand) 300 mg 3 times daily starting at 5 months postpartum. At 7 months postpartum, her breastfed (extent not stated) infant had a blood sample taken 8 hours after a dose. Neither hypericin (<0.2 mcg/L) nor hyperforin (<0.5 mcg/L) were detectable in the infant's plasma.[5]

Two infants were exclusively breastfed by mothers who had been taking St. John's wort (Jarsin brand) 300 mg 3 times daily for at least 4 weeks. Infant blood samples were taken when the infants were 10 and 22 weeks old, respectively. Both of their plasma hyperforin concentrations were at the limit of detection of 0.1 mcg/L.[6]

Effects in Breastfed Infants:

A woman took St. John's wort 300 mg daily (product details not specified) during pregnancy, discontinued it at term and then reinstituted it at 20 days postpartum. Her breastfed (extent not stated) infant was found to have a normal behavioral assessment on days 4 and 33.[7]

A postpartum woman with depression began taking St. John's wort (Jarsin brand) 300 mg 3 times daily starting at 5 months postpartum. At 7 months postpartum, no side effects were noted in her breastfed (extent not stated) infant and the infant's developmental score was normal.[5]

A matched cohort study compared 33 women who reported that they had taken St. John's wort during breastfeeding to 2 control groups who were either disease matched (primarily depression), or age and parity matched. The duration of breastfeeding was similar across all groups and ranged from a mean of 10.8 to 12.1 months. Formula was introduced on average between 4.3 and 6.3 months, with no statistical differences between groups. The brands of St. John's wort used were not reported. The average daily dosage was 705 mg (range 225 to 2150 mg daily), and the average duration of therapy was 1.5 months, beginning at 4.2 months (range 0 to 11 months) postpartum. The average duration of St. John's wort exposure in the infants via breastmilk was 2.1 months. Mothers who were taking St. John's wort more frequently reported infant colic (n = 2), drowsiness (n = 2) and lethargy (n = 1) than mothers in the other groups in which only 1 case of colic was reported in each group. The difference was statistically significant between the treatment and disease-matched control groups. Between these 2 groups, there were no differences in the proportion of women taking conventional antidepressants overall or among mothers of affected infants, or in the dosages the mothers took. None of the affected infants required specific medical treatment and there was no difference in weight gain between subsets of the groups in whom weight could be obtained between 15 and 16 months of age.[8]

Five women who were 10 to 22 weeks postpartum had been taking St. John's wort (Jarsin brand) 300 mg 3 times daily for at least 4 weeks and exclusively breastfeeding their infants. Mothers were asked if they had noticed any gastrointestinal symptoms, lethargy, rashes, photosensitivity, or changes in sleep pattern. None of the mothers observed any adverse effects or unusual behavior in their infants, and the infants grew normally during maternal therapy.[6]

Possible Effects on Lactation:

In a matched cohort study of 33 women who reported that they had taken St. John's wort during breastfeeding (described in more detail above in "Reported Side Effects In Breastfed Infants"), no evidence was found of lower milk production among mothers taking St. John's wort during breastfeeding.[8]

Thirty-six women with mild premenstrual syndrome received St. John's wort 450 mg twice daily as coated tablets (Jarsin brand) or placebo for two menstrual cycles. Serum prolactin levels of the women randomized to active treatment (n = 19) were not statistically different from those of the women who received placebo (n = 17) in either the follicular or luteal phase of their menstrual cycles.[9]

Studies in healthy volunteer males (n = 12) given single doses of 2700 mg of St. John's wort (Jarsin brand) had a drop in serum prolactin that was statistically significant between 150 and 210 minutes after administration.[10]

The prolactin level in a mother with established lactation may not affect her ability to breastfeed.

Alternate Drugs to Consider:



1. 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. PMID:10636495
2. Dennehy C, Tsourounis C, Bui L, King TL. The use of herbs by California midwives. J Obstet Gynecol Neonatal Nurs. 2010;39:684-93. PMID:21044150
3. Clauson KA, Santamarina ML, Rutledge JC. Clinically relevant safety issues associated with St. John's wort product labels. BMC Complement Altern Med. 2008;8:42. PMID:18637192
4. Wurglics M, Westerhoff K, Kaunzinger A et al. Comparison of German St. John's wort products according to hyperforin and total hypericin content. J Am Pharm Assoc (Wash). 2001;41:560-6. PMID:11486982
5. Klier CM, Schafer MR, Schmid-Siegel B et al. St. John's wort (</span>Hypericumperforatum) -- is it safe during breastfeeding? Pharmacopsychiatry. 2002;35:29-30. PMID:11819157
6. Klier CM, Schmid-Siegel B, Schafer MR et al. St. John's wort (</span>Hypericumperforatum) and breastfeeding: plasma and breast milk concentrations of hyperforin for 5 mothers and 2 infants. J Clin Psychiatry. 2006;67:305-9. PMID:16566628
7. Grush LR, Nierenberg A, Keefe B, Cohen LS. St John's wort during pregnancy. JAMA. 1998;280:1566. Letter. PMID:9820253
8. Lee A, Minhas R, Matsuda N et al. The safety of St. John's wort (</span>Hypericumperforatum) during breastfeeding. J Clin Psychiatry. 2003;64:966-8. PMID:12927015
9. Canning S, Waterman M, Orsi N et al. The efficacy ofHypericumperforatum (St John's wort) for the treatment of premenstrual syndrome: a randomized, double-blind, placebo-controlled trial. CNS Drugs. 2010;24:207-25. PMID:20155996
10. Franklin M , Cowen PJ. Researching the antidepressant actions ofHypericumperforatum (St. John's wort) in animals and man. Pharmacopsychiatry. 2001;34 (Suppl 1):S29-37. PMID:11518072

Substance Identification:

Substance Name:

St. John's Wort

Scientific Name:


CAS Registry Number:


Drug Class:

  • Anti-Anxiety Agents

  • Antidepressive Agents

  • Complementary Therapies

  • Phytotherapy

  • Plants, Medicinal

  • Administrative Information:

    LactMed Record Number:


    Last Revision Date:

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