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St. John's Wort (Hypericum perforatum) and Breastfeeding: Plasma and Breast Milk Concentrations of Hyperforin for 5 Mothers and 2 Infants

Claudia M. Klier, M.D.; Brigitte Schmid-Siegel, M.D., M.D.; Miriam R. Schäfer, M.D.; Gerhard Lenz, M.D.; Alois Saria, Ph.D.; Amy Lee, M.Sc.; and Gerald Zernig, M.D.

Background: Herbal preparations for depression, such as St. John's wort, are often preferred over pharmaceutical preparations by mothers and midwives after childbirth because these preparations are available to patients as over-the-counter "natural" treatments and are popularly assumed to be safe. The only existing report on St. John's wort excretion into human milk showed that only 1 active component (hyperforin) was detectable in breast milk, but was not detectable in the infants' plasma. Another report found more cases of minor problems in infants breast-fed by women taking St. John's wort. However, significance was reached only in comparison with disease-matched women (p < .01), not healthy controls (p = .20).

Method: Five mothers who were taking 300 mg of St. John's wort 3 times daily (LI 160 [Jarsin], Lichtwer Pharma GmbH; Berlin, Germany) and their breastfed infants were assessed. Thirty-six breast milk samples (foremilk and hindmilk collected during an 18-hour period) and 5 mothers' and 2 infants' plasma samples were analyzed for hyperforin levels by tandem mass spectrometry (LC/MS/MS; limit of quantification = 0.1 ng/mL). Data were gathered from January 2001 to February 2002.

Results: Hyperforin is excreted into breast milk at low levels. However, the compound was at the limit of quantification in the 2 infants' plasma samples (0.1 ng/mL). Milk/plasma ratios ranged from 0.04 to 0.13. The relative infant doses of 0.9% to 2.5% indicate that infant exposure to hyperforin through milk is comparable to levels reported in most studies assessing antidepressants or neuroleptics. No side effects were seen in the mothers or infants.

Conclusion: These results add to the evidence of the relative safety of St. John's wort while breast-feeding found in previous observational studies.

(J Clin Psychiatry 2006;67:305-309)

Received April 13, 2005; accepted Aug. 15, 2005. From the Departments of Child and Adolescent Neuropsychiatry (Drs. Klier and Schäfer) and Psychiatry (Drs. Schmid-Siegel and Lenz), Medical University Vienna, Vienna, Austria; the Division of Neurochemistry, Department of Psychiatry, Medical University Innsbruck, Innsbruck, Austria (Drs. Saria and Zernig); and the Division of Clinical Pharmacology and Toxicology, Hospital for Sick Children, Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada (Ms. Lee).

Lichtwer Pharma, Berlin, Germany, sponsored the analyses of the plasma and milk samples and the transport of the samples from Medical University Vienna to the Division of Neurochemistry at Medical University Innsbruck.

This work was presented at the Marcé Society International Biennial Scientific Meeting, September 23-26, 2004; Oxford, United Kingdom, and at the Marcé Annual Meeting of the German-speaking countries, October 22-23, 2004; Frankfurt, Germany.

The authors report no additional financial or other relationship relevant to the subject matter of this article.

Corresponding author and reprints: Claudia M. Klier, M.D., Department of Child and Adolescent Neuropsychiatry, Medical University Vienna, A-1090 Wien, Währinger Gürtel 18-20, AUSTRIA (e-mail: