How to Use Robitussin DM

Robitussin DM is an over-the-counter cough suppressant and expectorant. This medicine helps to control your cough and thin secretions so it is more productive. It is widely available under the brand name Robitussin and the same medicine may be purchased as a store brand or in generic form.

Robitussin cold medicine
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Common Uses

The ingredients in this medicine help to loosen mucus and suppress coughing. People commonly take this medicine for coughs associated with colds, allergies, the flu, and other respiratory illnesses.

Robitussin DM and its generic counterparts contain dextromethorphan HBr 10mg, which is a cough suppressant, and guaifenesin 100mg, which is an expectorant.

It should not be used in children under 6 without talking to the child's doctor first. 


  • Adults 12 and older: Two teaspoons every four hours as needed for cough. Do not take more than six doses in 24 hours.
  • Children ages 6 to 12: One teaspoon every four hours. Do not take more than six doses in 24 hours.

Side Effects

Every medication has the potential to cause side effects. Most are minor and the benefits outweigh the risks.

  • Drowsiness or dizziness
  • Hives or skin rash
  • Nausea, stomach pain or vomiting

Rare but serious side effects that should be reported to your healthcare provider immediately:

  • Confusion
  • Excitement, nervousness or restlessness
  • Severe nausea and vomiting
  • Slurred speech
  • Seizures or convulsions - in children
  • Shakey movements - in children
  • Slow or troubled breathing - in children


Do not use this medication if you are taking an MAOI (medication for depression, psychiatric, emotional conditions or Parkinson's disease) or for two weeks after stopping an MAOI.

Ask a healthcare provider before using this medicine if you have a chronic cough that is caused by asthma, smoking, or emphysema.

If you have a cough that produces a lot of mucus, taking a cough suppressant can be problematic. Suppressing the cough can lead to secondary infections such as pneumonia because the mucus sits in the lungs rather than being expelled by coughing.

Talk to your healthcare provider prior to taking this medicine if you are pregnant or breastfeeding as well.

Stop use and ask a healthcare provider if:

  • Pain or cough worsens or lasts more than seven days
  • Cough occurs with fever, headache, or rash that won't go away

Do not give Robitussin or other cough suppressants to children under 6.

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4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Shadkam MN, Mozaffari-Khosravi H, Mozayan MR. A Comparison of the Effect of Honey, Dextromethorphan, and Diphenhydramine on Nightly Cough and Sleep Quality in Children and Their ParentsThe Journal of Alternative and Complementary Medicine. 2010;16(7):787-793. doi:10.1089/acm.2009.0311

  2. Taylor CP, Traynelis SF, Siffert J, Pope LE, Matsumoto RR. Pharmacology of dextromethorphan: Relevance to dextromethorphan/quinidine (Nuedexta®) clinical usePharmacology & Therapeutics. 2016;164:170-182. doi:10.1016/j.pharmthera.2016.04.010

  3. Dolansky G, Rieder M. What is the evidence for the safety and efficacy of over-the-counter cough and cold preparations for children younger than six years of age?Paediatr Child Health. 2008;13(2):125–127. doi:10.1093/pch/13.2.125

  4. Bem JL, Peck R. Dextromethorphan An Overview of Safety IssuesDrug Safety. 1992;7(3):190-199. doi:10.2165/00002018-199207030-00004

Additional Reading
  • "Robitussin Cough Product Labeling." Wyeth Consumer Healthcare 2007.