Can I take phenoxymethylpenicillin while pregnant or breastfeeding?
A plain-words look at what the NHS, the US drug label and LactMed say about phenoxymethylpenicillin.
In short
Pregnancy: Phenoxymethylpenicillin can usually be taken in pregnancy, but it's best to ask a pharmacist or doctor first.
Breastfeeding: Phenoxymethylpenicillin can usually be taken during breastfeeding, but ask a doctor or pharmacist first.
Your doctor, midwife or pharmacist can help you decide.
When to get help
- Side effects in breastfed babies from medicines their mother takes are rare, but talk to a healthcare professional or call NHS 111 (in the UK) if anything about your baby worries you.
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
Phenoxymethylpenicillin in pregnancy
The NHS says
Phenoxymethylpenicillin can usually be taken in pregnancy, but it's best to ask a pharmacist or doctor first.
In our words, from the NHS page Phenoxymethylpenicillin (nhs.uk). Contains public sector information licensed under the Open Government Licence v3.0 (OGL v3.0). The NHS does not endorse this site.
More on phenoxymethylpenicillin in pregnancy: Bumps (Best Use of Medicines in Pregnancy) leaflet (external site).
Phenoxymethylpenicillin while breastfeeding
The NHS says
Phenoxymethylpenicillin can usually be taken during breastfeeding, but ask a doctor or pharmacist first.
Side effects in breastfed babies from medicines their mother takes are rare, but talk to a healthcare professional or call NHS 111 (in the UK) if anything about your baby worries you.
In our words, from the NHS page Phenoxymethylpenicillin (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
Limited information indicates that penicillin V produces low levels in milk that are not expected to cause adverse effects in breastfed infants. Occasionally disruption of the infant's gastrointestinal flora, resulting in diarrhea or thrush have been reported with penicillins, but these effects have not been adequately evaluated. Penicillin V is acceptable in nursing mothers.
“Summary of Use during Lactation”, LactMed record “Penicillin V” (LM210), quoted verbatim. Everything LactMed reports about Penicillin V while breastfeeding.
Sources
- NHS, Phenoxymethylpenicillin (nhs.uk), page last reviewed 1 September 2026. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
- Drugs and Lactation Database (LactMed), National Institute of Child Health and Human Development (NICHD), via NCBI Bookshelf, record “Penicillin V” (LM210), 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.