Tea tree (Melaleuca alternifolia)oilcontains primarily terpinen-4-ol, but more than 100 other constituents have been identified, including 1,8-cineole (eucalyptol). Tea treeoilshould not be confused with cajeputoil, niauoulioil, kanukaoil, or manukaoilwhich are obtained from Melaleuca species. Tea treeoilhas no specific lactation-related uses. It is usually used topically for the treatment of infections. No data exist on the excretion of any components of tea treeoilinto breastmilk or on the safety and efficacy of tea treeoilin nursing mothers or infants. Topical tea treeoilis generally well tolerated, but should not be taken orally. Tea treeoilmay have some minor estrogenic and antiandrogenic activity, so topical application around the breast should be avoided.
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Twelve nursing mothers who were19 weeks to 19 months postpartum ingested 100 mg of 1,8 cineole (eucalyptol) in the form of delayed-release capsules (Soledum-Klosterfrau Vertriebs GmbH, Germany) that release the drug in the intestine. Then they pumped 1 to 4 milk samples at the time they perceived the smell of eucalyptus on their breath which had been previously shown to be approximately concurrent. A total of 21 milk samples were obtained. Odor was rated by a panel of 3 to 5 experts as either smelling like eucalyptus or not. Fourteen of the samples had a distinct eucalyptus-like odor. Chemical analysis of the positive odor tests found 1,8-cineole in concentrations from 70 to about 2090 mcg/kg of milk, most in the range of 100 to 500 mcg/kg of milk. Samples with negative odor tests contained concentrations in the range of 0.98 to about 20.23 mcg/kg of milk. In one woman who donated 3 samples, the highest concentration of 71 mcg/kg occurred at 1.5 hours after ingestion, with concentrations of 1 mcg/kg before ingestion and 15 mcg/kg at 9.5 hours after ingestion.
Relevant published information was not found as of the revision date.
Effects in Breastfed Infants:
Nursing mothers who were participating in an experiment on the excretion of 1,8-cineole (eucalyptol) in breastmilk took a 100 mg capsule of 1,8-cineole orally. Although instructed not to, 12 mothers breastfed their infants during the experiment. Mothers reported that none of their infants refused their milk or breastfed less than usual. Two mothers felt that their infants were more agitated a few hours after breastfeeding. A third mother reported that the infant stopped nursing from time to time and "looked puzzled", but resumed nursing. Upon repeating the experiment 6 weeks later, the infant did not react in an unusual way during breastfeeding.
Possible Effects on Lactation:
Gynecomastia occurred in a prepubertal boy who was using a grooming product containing tea treeoil. The gynecomastia resolved after the product was discontinued. In vitro testing found that tea treeoilpossesses mild estrogenic and antiandrogenic activity. The relevance of these findings has been questioned, but no further testing has been reported to confirm or refute the findings as of the revision date.
1. Kirsch F, Beauchamp J, Buettner A. Time-dependent aroma changes in breast milk after oral intake of a pharmacological preparation containing 1,8-cineole. Clin Nutr. 2012. PMID:22405404 2. Henley DV, Lipson N, Korach KS, Bloch CA. Prepubertal gynecomastia linked to lavender and tea treeoils. N Engl J Med. 2007;356:479-85. PMID:17267908 3. Dean CJ. Prepubertal gynecomastia linked to lavender and tea treeoils. N Engl J Med. 2007;356:2543; author reply 2543-4. PMID:17575591 4. Kurtz JL. Prepubertal gynecomastia linked to lavender and tea treeoils. N Engl J Med. 2007;356:2542-3; author reply 2543-4. PMID:17575593 5. Kemper KJ, Romm AJ, Gardiner P. Prepubertal gynecomastia linked to lavender and tea treeoils. N Engl J Med. 2007;356:2541-2; author reply 2543-4. PMID:17568039 6. Kalyan S. Prepubertal gynecomastia linked to lavender and tea treeoils. N Engl J Med . 2007;356:2542; author reply 2543-4. PMID:17575592
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