Can I take erythromycin while pregnant or breastfeeding?
A plain-words look at what the NHS, the US drug label and LactMed say about erythromycin.
In short
Pregnancy: Let your doctor know if you're pregnant, or become pregnant, while taking erythromycin.
Breastfeeding: Let your doctor know if you're breastfeeding.
Your doctor, midwife or pharmacist can help you decide.
What this means for you
Pregnancy
- Erythromycin can be used in pregnancy if needed.
- Your doctor will go through the risks and benefits of taking it while pregnant with you.
Breastfeeding
- Erythromycin tablets, capsules and liquid can be taken while breastfeeding, but it's best to check first, as the medicine can get into your breast milk.
- Your doctor will talk it through with you and may advise you to keep taking erythromycin if the benefits for you are greater than the risks for your baby.
- If you use erythromycin lotion while breastfeeding, it's unlikely any will reach your breast milk.
- If you apply it to your chest, rinse it off with warm water before you feed your baby.
- Side effects in breastfed babies from medicines their mother uses are rare, but speak to a healthcare professional if you're worried about your baby.
Talk to your doctor or pharmacist
This page is educational, not advice for your own situation. Talk to your doctor, midwife or pharmacist before you start, stop or change any medicine in pregnancy or while breastfeeding.
The details: what each source says
Erythromycin in pregnancy
The NHS says
Let your doctor know if you're pregnant, or become pregnant, while taking erythromycin.
Erythromycin can be used in pregnancy if needed. Your doctor will go through the risks and benefits of taking it while pregnant with you.
In our words, from the NHS page Erythromycin (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
The US drug label says
Pregnancy: Teratogenic Effects There is no evidence of teratogenicity or any other adverse effect on reproduction in female rats fed erythromycin base by oral gavage at 350 mg/kg/day (approximately twice the maximum recommended human dose on a body surface area) prior to and during mating, during gestation, and through weaning. No evidence of teratogenicity or embryotoxicity was observed when erythromycin base was given by oral gavage to pregnant rats and mice at 700 mg/kg/day and to pregnant rabbits at 125 mg/kg/day (approximately 1 to 3 times the maximum recommended human dose).
Prescribing label, section “Pregnancy”: E.E.S 400 (oral), REMEDYREPACK INC. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
More on erythromycin in pregnancy: Bumps (Best Use of Medicines in Pregnancy) leaflet (external site).
Erythromycin while breastfeeding
The NHS says
Let your doctor know if you're breastfeeding.
Erythromycin tablets, capsules and liquid can be taken while breastfeeding, but it's best to check first, as the medicine can get into your breast milk.
Your doctor will talk it through with you and may advise you to keep taking erythromycin if the benefits for you are greater than the risks for your baby.
If you use erythromycin lotion while breastfeeding, it's unlikely any will reach your breast milk. If you apply it to your chest, rinse it off with warm water before you feed your baby.
Side effects in breastfed babies from medicines their mother uses are rare, but speak to a healthcare professional if you're worried about your baby.
In our words, from the NHS page Erythromycin (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
LactMed says
Because of the low levels of erythromycin in breastmilk and safe administration directly to infants, it is acceptable in nursing mothers. The small amounts in milk are unlikely to cause adverse effects in the infant. Monitor the infant for irritability and possible effects on the gastrointestinal flora, such as diarrhea, candidiasis (thrush, diaper rash). One case report and unconfirmed epidemiologic evidence indicates that hypertrophic pyloric stenosis in infants might occur with maternal use of erythromycin during the first two weeks of breastfeeding; however, if it occurs, the frequency is very low and others have questioned this relationship.
Infant side effects are unlikely with topical application for acne, although topical application to the nipple may increase the risk of diarrhea in the infant. Only water-miscible cream or gel products should be applied to the breast because ointments may expose the infant to high levels of mineral paraffins via licking.[1]
“Summary of Use during Lactation”, LactMed record “Erythromycin” (LM351), quoted verbatim. Everything LactMed reports about Erythromycin while breastfeeding.
The US prescribing label says
Nursing Mothers: Erythromycin is excreted in human milk. Caution should be exercised when erythromycin is administered to a nursing woman.
Prescribing label, section “Nursing Mothers”: E.E.S 400 (oral), REMEDYREPACK INC. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
Sources
- NHS, Erythromycin (nhs.uk), page last reviewed 28 July 2026. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
- US drug label: E.E.S 400 (oral), REMEDYREPACK INC., human prescription drug, label effective 23 June 2026, set ID 49b3ca93-43cc-439c-8f5d-e3ea2e87ad2f. DailyMed (National Library of Medicine). Public domain; quoted verbatim.
- Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Erythromycin” (LM351), bulk release of 22 September 2026. LactMed on NCBI Bookshelf. Public domain; quoted verbatim. LactMed is a registered trademark of the U.S. Department of Health and Human Services.
- Bumps (Best Use of Medicines in Pregnancy), UK Teratology Information Service: Bumps (Best Use of Medicines in Pregnancy) leaflet. Linked, not reproduced.
Sources checked 26 September 2026. How we source and check every page.
Educational summary of named sources, not medical advice.