Can I Take DayQuil While Breastfeeding? DayQuil and NyQuil, Ingredient by Ingredient

You’re nursing, you feel awful, and there’s a bottle of DayQuil in the cupboard. Can you take it? For most breastfeeding parents the answer is yes for a few days, with two things to check first: which DayQuil you have, and how much acetaminophen you’re already taking.

“DayQuil” and “NyQuil” are brand families, not single products. The versions on the shelf contain different mixes of ingredients, and one or two of those ingredients matter for your milk supply. This page goes through the DayQuil and NyQuil labels we read on DailyMed, one ingredient at a time, using LactMed, the National Library of Medicine’s database on drugs and breastfeeding. For cold medicine in general, including Mucinex and sprays, see our guide to cold medicine while breastfeeding, and for other medicines our hub on what’s safe while breastfeeding.

What’s in DayQuil and NyQuil

Here are the versions we checked. Formulas change, so read the “Active ingredients” box on your own package.

Product (as labeled)	Active ingredients	Breastfeeding notes
DayQuil Cold & Flu (liquid, LiquiCaps)	Acetaminophen, dextromethorphan, phenylephrine	Phenylephrine might lower supply
DayQuil Severe Cold & Flu	Same as above plus guaifenesin	As above
DayQuil-D Cold & Sinus	Acetaminophen, dextromethorphan, guaifenesin, pseudoephedrine	Pseudoephedrine can lower supply
DayQuil Intense Flu (liquid)	Acetaminophen, dextromethorphan	No decongestant; lists alcohol as an inactive ingredient
NyQuil Cold & Flu (liquid, LiquiCaps)	Acetaminophen, dextromethorphan, doxylamine	Drowsy antihistamine; liquid is 10% alcohol
NyQuil Severe Cold & Flu (liquid)	Adds phenylephrine to the above	Drowsiness plus the phenylephrine caution
NyQuil Alcohol Free Cold & Flu	Acetaminophen, chlorpheniramine, dextromethorphan	Different antihistamine, no alcohol
NyQuil-D Cold & Sinus	Acetaminophen, dextromethorphan, doxylamine, pseudoephedrine	Best avoided while nursing

Every DayQuil and NyQuil label we opened says: “If pregnant or breast-feeding, ask a health professional before use.” That’s standard wording, so use it as a reason to ask your pharmacist, not as a ban.

The ingredients, one by one

Acetaminophen (pain and fever)

LactMed calls acetaminophen a good choice for pain and fever in nursing mothers. It says the amounts in milk are much less than doses usually given to infants, and adverse effects in breastfed babies appear to be rare.

The real risk with DayQuil is doubling up. The DayQuil Cold & Flu liquid label has a liver warning: severe liver damage may occur if you take more than the maximum daily amount, take it with other drugs containing acetaminophen, or have 3 or more alcoholic drinks every day while using it. Each 15 mL of DayQuil liquid has 325 mg of acetaminophen, and each 30 mL cup of NyQuil liquid has 650 mg. If you take DayQuil by day and NyQuil at night, both count toward the same daily limit, and so does any Tylenol. Our guide to ibuprofen and Tylenol while breastfeeding covers pain relief on its own.

Dextromethorphan (cough)

LactMed says that when it’s used as a cough syrup, the amounts of dextromethorphan and its active metabolite in breast milk are very low and not expected to affect a nursing baby. It adds one caveat: it’s best to avoid products with a high alcohol content while nursing (more on NyQuil’s alcohol below).

Phenylephrine (the decongestant in regular DayQuil)

This is the ingredient that deserves a second look. LactMed says so little phenylephrine is absorbed when swallowed that it’s unlikely to reach your baby. But it also says oral phenylephrine might decrease milk production, and that another drug may be preferred, especially with a newborn or preterm baby. Phenylephrine nasal sprays are less likely to affect lactation.

There’s a second reason to skip it: the FDA has proposed removing oral phenylephrine as an over-the-counter decongestant because its review found it isn’t effective. The FDA page we read (current as of November 2024) says the proposal isn’t final and products can stay on shelves until it is. So if congestion isn’t your main problem, a DayQuil version without phenylephrine, such as the Intense Flu formula, gives you the pain and cough relief without the supply question.

Pseudoephedrine (DayQuil-D and NyQuil-D)

The “-D” versions swap in pseudoephedrine, the decongestant most clearly linked to a drop in milk supply. LactMed says a single dose decreases milk production acutely and repeated use seems to interfere with lactation, and that it should not be used by mothers of newborns or anyone having trouble making enough milk. Our page on Sudafed while breastfeeding explains the study behind that warning.

Guaifenesin (DayQuil Severe, DayQuil-D)

LactMed says guaifenesin hasn’t been studied in breastfeeding, but usual doses are unlikely to harm a nursing baby, especially after 2 months of age.

NyQuil while breastfeeding

NyQuil’s sleep ingredient is doxylamine, a sedating antihistamine. LactMed says small, occasional doses would not be expected to cause adverse effects in breastfed babies. Larger doses or longer use may cause drowsiness in the baby or decrease milk supply, particularly when combined with a decongestant such as pseudoephedrine or before breastfeeding is well established. That combination is exactly what NyQuil-D contains.

NyQuil Alcohol Free uses chlorpheniramine (4 mg per 30 mL) instead. LactMed says small, occasional doses of 2 to 4 mg are acceptable, that a single bedtime dose after the last feeding of the day may be enough for many women, and that the non-drowsy antihistamines are preferred alternatives. Our guide to Benadryl while breastfeeding covers sedating antihistamines in more depth.

If you take any nighttime formula:

• Take it right after a feed, ideally the last one before a longer stretch.
• Have another adult handle the next night feed if you can.
• Don’t bring your baby into your bed. The AAP says it’s extra important not to bed share if you’ve taken any medicines that make you harder to wake.

What about the alcohol in liquid NyQuil?

The NyQuil Cold & Flu liquid label states “Alcohol 10%”, and the adult dose is 30 mL. That works out to about 3 mL of pure alcohol per dose (our calculation). The CDC defines a standard drink as 0.6 ounces of pure alcohol, roughly 18 mL (our conversion), so one dose of liquid NyQuil holds about a sixth of a drink (also our calculation).

The CDC says up to one drink a day is not known to be harmful to a breastfed baby, and that waiting 2 hours per drink before nursing is the safest approach. So the alcohol in one dose is small, but LactMed’s advice on cough products is to avoid high-alcohol ones while nursing. The LiquiCaps and NyQuil Alcohol Free don’t list alcohol among their inactive ingredients, which makes them simpler choices. Our breastfeeding and alcohol guide has more on timing.

A simple way to choose

1. Treat only the symptoms you have. Cough and aches without a stuffy nose? A version without a decongestant makes sense.
2. Avoid anything labeled “-D” if your baby is a newborn or your supply is low or still settling.
3. Count your acetaminophen across every product you take.
4. At night, choose the smallest sedating dose and keep your baby on their own sleep surface.
5. Use non-drug help too. The CDC suggests saline nasal spray or drops and a clean humidifier for colds. Our guide to breastfeeding while sick covers rest, fluids and keeping your baby fed.

When to call a doctor or lactation consultant

The DayQuil label says to stop and ask a doctor if you get nervous, dizzy or sleepless, if symptoms get worse or last more than 7 days, if a fever gets worse or lasts more than 3 days, or if new symptoms appear. The CDC adds trouble breathing or fast breathing, dehydration, and symptoms that improve and then return or get worse.

Call your baby’s doctor if your baby is unusually sleepy, hard to wake for feeds, feeding less than usual or unusually irritable after you take a cold medicine, or if your baby shows signs of being sick. Ask a pharmacist before taking any DayQuil or NyQuil product if your baby is a newborn or was born early, or if you take other medicines. If your supply drops after a decongestant, an IBCLC can help you build it back; our breastfeeding support page lists where to find one.