Only if your Robitussin is the plain guaifenesin kind, like Robitussin Mucus + Chest Congestion, and your DayQuil is the original Cold & Flu. Robitussin DM, CF and Severe Multi-Symptom all contain dextromethorphan, the same cough suppressant already in DayQuil, so taking them together doubles that dose. Robitussin Severe Multi-Symptom also contains acetaminophen, and the DayQuil label says not to use it with any other acetaminophen product. Read the active ingredients on both boxes before you take either.
What is in DayQuil?
Original Vicks DayQuil Cold & Flu LiquiCaps contain 3 active ingredients per LiquiCap, according to the label on DailyMed.
Other DayQuil boxes, such as DayQuil Severe and DayQuil High Blood Pressure, have different ingredient lists. Check which box you actually have and read its Drug Facts before you add anything.
- Acetaminophen 325 mg - pain reliever and fever reducer (the drug in Tylenol)
- Dextromethorphan HBr 10 mg - cough suppressant
- Phenylephrine HCl 5 mg - nasal decongestant
Which Robitussin is in your hand?
Robitussin sells many formulas under one name. The letters and words on the front tell you a lot, but the Drug Facts box is the only thing that counts. Here is what the DailyMed labels list per dose:
- Robitussin Mucus + Chest Congestion - guaifenesin 200 mg per 10 mL only. No overlap with original DayQuil.
- Robitussin Cough + Chest Congestion DM (Maximum Strength) - dextromethorphan 20 mg and guaifenesin 400 mg per 20 mL. Doubles the dextromethorphan in DayQuil.
- Robitussin Peak Cold Multi-Symptom Cold CF - dextromethorphan 20 mg, guaifenesin 200 mg and phenylephrine 10 mg per 10 mL. Doubles both the cough suppressant and the decongestant.
- Robitussin Severe Multi-Symptom Cough Cold + Flu - acetaminophen 650 mg, dextromethorphan 20 mg, guaifenesin 400 mg and phenylephrine 10 mg per 20 mL. Overlaps with every active ingredient in DayQuil.
Why is doubling dextromethorphan a problem?
A dose of Robitussin DM Maximum Strength has 20 mg of dextromethorphan. A dose of DayQuil (2 LiquiCaps) has another 20 mg. Take them at the same time and you get double the cough suppressant, and both labels allow a dose every 4 hours.
MedlinePlus warns that cough and cold products may contain the same active ingredients and that taking them together could cause an overdose. It lists overdose symptoms of dextromethorphan as nausea, vomiting, drowsiness, dizziness, unsteadiness, vision changes, trouble breathing, fast heartbeat, hallucinations, seizures and coma.
If you want a cough suppressant and DayQuil's other ingredients, DayQuil already gives you both. Adding a DM product does not add a new kind of relief.
What about acetaminophen and the decongestant?
The DayQuil label says not to use it with any other drug that contains acetaminophen, prescription or not. It warns that severe liver damage may occur if you take more than 8 LiquiCaps in 24 hours, take other acetaminophen products, or have 3 or more alcoholic drinks a day while using it. Robitussin Severe Multi-Symptom contains acetaminophen and carries the same warning, so do not take these 2 together. Tylenol is acetaminophen too, so it counts.
Phenylephrine is the decongestant in original DayQuil, Robitussin CF and Robitussin Severe. The Robitussin Severe and CF labels say to ask a doctor or pharmacist before use if you take another oral nasal decongestant. Do not double up on a decongestant. If you have high blood pressure or heart disease, all 3 of these labels say ask a doctor before use.
Advil and Motrin are ibuprofen. Neither Robitussin nor DayQuil lists ibuprofen as an ingredient, so that question is a different one, covered on our DayQuil and ibuprofen page.
When should you get care?
In an emergency, call 911Get medical help or call Poison Control at 1-800-222-1222 right away if you think you took too much acetaminophen, even if you feel fine. The DayQuil label says to do this even without signs or symptoms.
Call Poison Control at 1-800-222-1222 right away if you doubled up on dextromethorphan and feel drowsy, dizzy, unsteady, sick to your stomach, or your heart is racing.
Stop and get medical help right away if you get skin reddening, blisters or a rash after taking an acetaminophen product.
See a clinician if your cough lasts more than 7 days or keeps coming back, your fever lasts more than 3 days, or a cough comes with fever, rash or a headache that will not go away.
Call 911 if someone collapses, has a seizure, has trouble breathing, cannot be woken up, or is seeing or hearing things that are not there.
How our AI doctor decides when to send you to care ›Who should ask a pharmacist first, even with plain Robitussin?
Plain guaifenesin and original DayQuil do not share an ingredient, but each label still lists people who should check before use. These come from the DayQuil and Robitussin labels:
- You take an MAOI (certain antidepressants, psychiatric or Parkinson's drugs), or stopped one in the last 2 weeks. The DayQuil, Robitussin DM, CF and Severe labels all say do not use.
- High blood pressure, heart disease, thyroid disease, diabetes, or trouble urinating from an enlarged prostate - the DayQuil label says ask a doctor before use.
- Liver disease, or you take warfarin - ask first, per the DayQuil label.
- A cough with a lot of phlegm, or a long-term cough such as from smoking, asthma or emphysema - the DayQuil and Robitussin labels all say ask a doctor before use.
- Pregnant or breastfeeding - both labels say ask a health professional.
- Children under 12 - the adult Robitussin labels say do not use. DayQuil says ask a doctor for ages 4 to under 12 and do not use under 4.
Common questions
Can I take Robitussin and DayQuil together?
Plain Robitussin (guaifenesin only) and original DayQuil Cold & Flu share no active ingredients. Robitussin DM, CF and Severe Multi-Symptom all contain dextromethorphan, which DayQuil already has, so do not take those together. Check both Drug Facts boxes, and ask a pharmacist if you take other medicines or have a condition the labels list.
Can I take Robitussin DM with DayQuil if I space them out?
Spacing does not fix the overlap. Both products are dosed every 4 hours, so their dextromethorphan still adds up across the day. Pick one product that covers the symptoms you have.
Can I take plain Robitussin with DayQuil Severe?
Read the DayQuil Severe box first. If its active ingredients include guaifenesin, adding plain Robitussin would double the guaifenesin. Choose one or the other, or ask a pharmacist.
Can I take Robitussin during the day and NyQuil at night?
It depends on which formulas. Some NyQuil products, such as NyQuil High Blood Pressure, list dextromethorphan and acetaminophen along with a sleep aid, so a Robitussin DM dose late in the day can overlap with a NyQuil dose at bedtime. Compare the active ingredients on both labels and ask a pharmacist how far apart to take them.
Is Robitussin DM stronger than DayQuil for a cough?
A 20 mL dose of Robitussin DM Maximum Strength has 20 mg of dextromethorphan. A 2 LiquiCap dose of DayQuil also has 20 mg. The cough suppressant dose is the same; DayQuil adds acetaminophen and a decongestant, Robitussin DM adds guaifenesin.
Pymander is not a replacement for a physician and does not provide medical advice, diagnosis, or treatment. Always seek the advice of a qualified health provider with questions about a medical condition. If you think you may have a medical emergency, call 911.