Compare Benadryl vs. Robitussin DM

Head-to-head comparisons of medication uses, side effects, ratings, and more.

Benadryl (Diphenhydramine)

Prescription or OTC
Treats allergy symptoms and helps you sleep.

Benadryl (Diphenhydramine) is great for allergies, but curl up on the couch after taking it and get ready for a nap.

5.6/ 7 average rating with 294 reviewsforBenadryl
Breaks up mucus and relieves cough.

Robitussin Dm (Guaifenesin / Dextromethorphan) is okay for loosening congestion in your chest and throat, but it could prevent you from coughing the mucus up. You have to take it more often than other guaifenesin products.

5.0/ 7 average rating with 724 reviewsforRobitussin DM
Upsides
  • Benadryl (Diphenhydramine) is often better than other antihistamines at treating allergy symptoms and hives.
  • It can provide quick relief of allergy symptoms for both kids and adults.
  • It makes you sleepy, so it'll help if your allergies are bothering you at night.
  • The effects wear off in 4 to 6 hours, so side effects don't last that long.
  • It comes as a tablet, capsule, liquid, and quick dissolving tablet.
  • Robitussin Dm (Guaifenesin / Dextromethorphan) is a combination medicine that relieves multiple cold symptoms. It's good to use if you have chest congestion and a cough.
  • Helps loosen the mucus and phlegm that builds up and causes productive, wet coughs.
Downsides
  • Benadryl (Diphenhydramine) makes you more tired than Claritin, Allegra, or Zyrtec.
  • You shouldn't drive after taking Benadryl (Diphenhydramine) until you know how it affects you.
  • Talk to a pediatrician before giving Benadryl (Diphenhydramine) to a child.
  • It can increase the risk of falls, so elderly people shouldn't use Benadryl (Diphenhydramine).
  • Don't use Benadryl (Diphenhydramine) if you are breastfeeding.
  • Robitussin Dm (Guaifenesin / Dextromethorphan) isn’t useful if you have a dry cough without mucus or phlegm.
  • The two medications in this product could potentially work against each other. Guaifenesin makes mucus easier to cough up, while dextromethorphan (the "DM" in Robitussin Dm (Guaifenesin / Dextromethorphan)) stops you from coughing.
  • Needs to be taken more often during the day than other products with guaifenesin, like Mucinex.
  • Can cause sleepiness, dizziness, and an upset stomach.
Used for
Dosage forms
  • Pill
  • Oral solution
  • Cream, gel, or ointment
  • Liquid
No pricing information available
No pricing information available
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Reviews
294 
86%
think this treatment is worth it
59%
think this treatment works well
8%
think this treatment is a hassle

Have you used Benadryl (Diphenhydramine)?

Leave a review
724 
75%
think this treatment is worth it
37%
think this treatment works well
7%
think this treatment is a hassle

Have you used Robitussin Dm (Guaifenesin / Dextromethorphan)?

Leave a review
Side effects
The Benadryl (Diphenhydramine) FDA package insert doesn’t have numbers about how common side effects are.
The Robitussin Dm (Guaifenesin / Dextromethorphan) FDA package insert doesn’t have numbers about how common side effects are.
Risks and warnings
  • Overdose

    Using other drugs with the same ingredients

  • Increased side effects

    Age 65 years or older

  • Driving impairment

    Taking with alcohol

    ...and 1 more risk factors

  • Hyperactivity

    Children age 6 years and younger

  • Trouble urinating

    Enlarged prostate

    ...and 1 more risk factors

  • Vision changes

    Glaucoma

  • Breastfeeding

    Nursing mothers

See more detailed risks and warnings
  • Serotonin syndrome

    Using other medications that affect serotonin

See more detailed risks and warnings