Can I take diphenhydramine while pregnant or breastfeeding?
A plain-words look at what the NHS, the US drug label and LactMed say about diphenhydramine.
In short
Pregnancy: Diphenhydramine can be used in pregnancy, but it's not normally recommended.
Breastfeeding: You can take diphenhydramine tablets or liquid while breastfeeding if your baby is healthy.
Your doctor, midwife or pharmacist can help you decide.
What this means for you
Pregnancy
- This is because its side effects of daytime drowsiness and dizziness may be worse while you're pregnant.
- Ask your doctor or pharmacist about other antihistamines that may suit you better, such as chlorphenamine.
- If you're having trouble sleeping in pregnancy, your doctor or midwife can suggest ways to sleep better.
- If you have a cough or cold, resting, drinking lots of fluids and taking paracetamol can help ease your symptoms.
Breastfeeding
- Very small amounts of diphenhydramine get into breast milk, and side effects in your baby are unlikely.
- However, as it could make your baby sleepy, it's better to take it only now and then or for a short time.
- Other medicines that don't cause drowsiness might be better, particularly if you need something for longer.
- Diphenhydramine products bought from a pharmacy may contain other ingredients too, so if you're breastfeeding, ask a pharmacist or doctor before using them.
- You can use diphenhydramine cream while breastfeeding.
- It's not thought to get into breast milk or to cause side effects in breastfed babies.
- Make sure your baby does not touch any part of your body where you've put it, and wash your hands after using it and before you pick up your baby.
- Side effects in breastfed babies from medicines their mother takes are very rare, but it's important to keep an eye on your baby whenever you take a medicine while breastfeeding.
- Carry on breastfeeding as normal until you've had advice about your baby's symptoms.
- It's important that you do not share a bed with your baby while taking diphenhydramine tablets or liquid.
When to get help
- Contact a healthcare professional or call 111 (NHS 111 in the UK) as soon as you can if your baby is not feeding normally or not waking for feeds, seems unusually sleepy, or is irritable.
- For symptoms not mentioned here, or if you're worried about your baby, you can also speak to any healthcare professional or call 111.
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
Diphenhydramine in pregnancy
The NHS says
Diphenhydramine can be used in pregnancy, but it's not normally recommended. This is because its side effects of daytime drowsiness and dizziness may be worse while you're pregnant.
Ask your doctor or pharmacist about other antihistamines that may suit you better, such as chlorphenamine.
If you're having trouble sleeping in pregnancy, your doctor or midwife can suggest ways to sleep better.
If you have a cough or cold, resting, drinking lots of fluids and taking paracetamol can help ease your symptoms.
In our words, from the NHS page Diphenhydramine (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
If pregnant or breast-feeding , ask a health professional before use.
Drug Facts label: Nighttime Sleep Aid Berry Flavor (oral), Raritan Pharmaceuticals Inc. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
Pregnancy Pregnancy Category B Reproduction studies have been performed in rats and rabbits at doses up to 5 times the human dose and have revealed no evidence of impaired fertility or harm to the fetus due to diphenhydramine hydrochloride. There are, however, no adequate and well-controlled studies in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.
Prescribing label, section “Pregnancy”: Diphenhydramine HCL (oral), Redmont Pharmaceuticals, LLC. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
Diphenhydramine while breastfeeding
The NHS says
You can take diphenhydramine tablets or liquid while breastfeeding if your baby is healthy.
Very small amounts of diphenhydramine get into breast milk, and side effects in your baby are unlikely. However, as it could make your baby sleepy, it's better to take it only now and then or for a short time. Other medicines that don't cause drowsiness might be better, particularly if you need something for longer.
Diphenhydramine products bought from a pharmacy may contain other ingredients too, so if you're breastfeeding, ask a pharmacist or doctor before using them.
You can use diphenhydramine cream while breastfeeding. It's not thought to get into breast milk or to cause side effects in breastfed babies. Make sure your baby does not touch any part of your body where you've put it, and wash your hands after using it and before you pick up your baby.
Side effects in breastfed babies from medicines their mother takes are very rare, but it's important to keep an eye on your baby whenever you take a medicine while breastfeeding.
Contact a healthcare professional or call 111 (NHS 111 in the UK) as soon as you can if your baby is not feeding normally or not waking for feeds, seems unusually sleepy, or is irritable.
For symptoms not mentioned here, or if you're worried about your baby, you can also speak to any healthcare professional or call 111.
Carry on breastfeeding as normal until you've had advice about your baby's symptoms.
It's important that you do not share a bed with your baby while taking diphenhydramine tablets or liquid.
In our words, from the NHS page Diphenhydramine (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
Small (25 mg or less), occasional doses of diphenhydramine would not be expected to cause any adverse effects in breastfed infants. Larger doses or more prolonged use may cause effects in the infant or decrease the milk supply, particularly in combination with a sympathomimetic such as pseudoephedrine or before lactation is well established. Single bedtime doses after the last feeding of the day may be adequate for many women and will minimize any effects of the drug. The nonsedating antihistamines are preferred alternatives.
“Summary of Use during Lactation”, LactMed record “Diphenhydramine” (LM96), quoted verbatim. Everything LactMed reports about Diphenhydramine while breastfeeding.
What these words mean
- contraindicated
- there is a reason not to use this medicine, because it may be harmful
Definitions adapted from the NCI Dictionary of Cancer Terms (National Cancer Institute).
The US prescribing label says
Nursing Mothers Because of the higher risk of antihistamines for infants generally, and for neonates and prematures in particular, antihistamine therapy is contraindicated in nursing mothers.
Prescribing label, section “Nursing Mothers”: Diphenhydramine (intramuscular, intravenous), Avenacy, LLC. Label on DailyMed. Quoted verbatim; US labels are written for US prescribers and patients.
This quote is from the intramuscular/intravenous formulation label.
Other names
UK brand names (per the NHS): Nytol Original, Boots Sleepeaze, Histergan.
Sources
- NHS, Diphenhydramine (nhs.uk), page last reviewed 13 May 2025. Paraphrased. Contains public sector information licensed under the Open Government Licence v3.0.
- US drug label: Nighttime Sleep Aid Berry Flavor (oral), Raritan Pharmaceuticals Inc, human otc drug, label effective 9 September 2026, set ID 303d7651-9c8f-4a14-9f2c-7181fa0f003e. DailyMed (National Library of Medicine). Public domain; quoted verbatim.
- US drug label: Diphenhydramine HCL (oral), Redmont Pharmaceuticals, LLC, human prescription drug, label effective 3 August 2026, set ID d8944f3c-acef-4ebe-9633-7d641ae95edf. DailyMed (National Library of Medicine). Public domain; quoted verbatim.
- US drug label: Diphenhydramine (intramuscular, intravenous), Avenacy, LLC, human prescription drug, label effective 16 May 2025, set ID 00f862aa-6917-45c7-b6aa-1bebb0a45e14. 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 “Diphenhydramine” (LM96), 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.
Sources checked 26 September 2026. How we source and check every page.
Educational summary of named sources, not medical advice.