Summary of Use during Lactation

Oregano (Origanum vulgare) leaves and oil contain carvacrol, thymol, eugenol and rosmarinic acid. Oregano has been used in medicinal doses for respiratory and gastrointestinal disorders and as an antimicrobial. Oregano oil has been advocated as a treatment for lactation-related Candida infection of the nipples;[1] however, no clinical studies have confirmed the safety or efficacy of this use. Oregano has been used as a galactogogue in Türkiye.[2] No data exist on the safety or efficacy of oregano in nursing mothers or infants. Oregano and oregano oil are "generally recognized as safe" (GRAS) as food ingredients by the U.S. Food and Drug Administration. Oregano is generally well tolerated, but gastrointestinal upset and allergic skin reactions have been reported rarely. Because of a lack of data, oregano in amounts higher than those found in foods as a flavoring should probably be avoided during breastfeeding.

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. Twenty nursing mothers who were nursing their infants with a mean of 25 weeks of age were served a standardized curry dish that contained an average of 1.1 mg of eugenol, and 35 mg of linalool. Mothers donated one milk sample each before and 1, 2, 3, 4, 5, 6, and 8 h after the eating the curry dish. Eugenol reached its maximum concentration in milk after 1 hour in two participants, after 2 hours in two participants, after 3 hours in three participants, after 4 hours in one participant after 5 hours in two participants, after 6 hours in three participants and after 8 hours in three participants. In seven participants, eugenol was not detected in milk. Peak milk eugenol concentrations ranged from 0.29 to 11.43 mcg/L. Eugenol concentrations averaged 200% higher after milk samples were treated with beta-glucuronidase, indicating transfer of conjugated eugenol into milk.[3]

Infant Levels. Relevant published information was not found as of the revision date.

Effects in Breastfed Infants

Relevant published information was not found as of the revision date.

Effects on Lactation and Breastmilk

Relevant published information was not found as of the revision date.

References

1.

Jacobsen PJ. Candida versus breastfeeding--which is winning? Midwifery Today Int Midwife 2009:26-7, 66. [PubMed: 19627056]

2.

Erarslan ZB, Kültür S. Medicinal plants traditionally used to increase breast milk in Turkey: An ethnobotanical review. J Herbal Med 2024;44:100849. doi:10.1016/j.hermed.2024.100849 [CrossRef]

3.

Debong MW, Homm I, Gigl M, et al. Curry-odorants and their metabolites transfer into human milk and urine. Mol Nutr Food Res 2024;68:e2300831. [PubMed: 38602198]

Substance Name

Oregano

Scientific Name

Origanum vulgare

Drug Class

Breast Feeding

Lactation

Milk, Human

Complementary Therapies

Food

Phytotherapy

Plants, Medicinal