Cough medicine
We research products from makers' specs and health sources; we do not run hands-on tests. Links to Amazon may earn us a commission at no cost to you. How this works.
- Delsym 12 Hour cough relief liquid. Best for: Long-lasting relief of a dry cough. See options on Amazon
- Robitussin Cough + Chest Congestion DM. Best for: Cough with chest congestion. See options on Amazon
- Oral medicine dosing syringe and cup set. Best for: Measuring liquid doses accurately. See options on Amazon
Delsym vs Robitussin DM
| Detail | Delsym 12 Hour liquid | Robitussin DM |
|---|---|---|
| Active ingredients | DM polistirex, equal to 30 mg DM HBr per 5 mL | DM HBr 20 mg and guaifenesin 200 mg per 20 mL |
| Adult dose (12 and over) | 10 mL every 12 hours; max 20 mL in 24 hours | 20 mL every 4 hours; max 6 doses in 24 hours |
| Children | Doses from age 4; under 4: do not use | Adult product; under 12: do not use |
DM stands for dextromethorphan; the Robitussin product's full name is Robitussin Cough + Chest Congestion DM. Details are from each product's DailyMed label. Both say measure only with the dosing cup provided.
What dextromethorphan does
The Delsym label lists its purpose as cough suppressant: it temporarily relieves cough due to minor throat and bronchial irritation as may occur with the common cold or inhaled irritants, and relieves the impulse to cough to help you get to sleep. Robitussin DM adds guaifenesin, an expectorant that helps loosen phlegm and thin bronchial secretions.
Pick by your cough: a dry, tickly cough may suit a plain suppressant, while a chesty cough with mucus may suit a DM plus guaifenesin product or plain guaifenesin. See our guaifenesin guide.
Children's doses and FDA advice
- Delsym, ages 6 to under 12: 5 mL every 12 hours, not more than 10 mL in 24 hours.
- Delsym, ages 4 to under 6: 2.5 mL every 12 hours, not more than 5 mL in 24 hours.
- Under 4: do not use, per the Delsym label.
The FDA does not recommend OTC medicines for cough and cold symptoms in children younger than 2, and says manufacturers label these products not to use in children under 4. It advises using the dosing device that comes with the medicine, not household spoons. For young children, see our honey cough syrup guide and cool mist humidifier guide.
Warnings
- MAOIs. Do not use if you take a prescription monoamine oxidase inhibitor (for depression, psychiatric or emotional conditions, or Parkinson's disease), or for 2 weeks after stopping one. Ask a doctor or pharmacist if unsure.
- Ask a doctor first for a chronic cough, such as occurs with smoking, asthma, chronic bronchitis or emphysema, or a cough with too much phlegm.
- Pregnancy or breastfeeding: ask a health professional before use.
- Overdose: get medical help or contact a Poison Control Center right away.
Avoid doubling up
Dextromethorphan appears in many multi-symptom cold, flu and nighttime products. Taking a cough syrup with a combination cold medicine can mean a double dose of dextromethorphan, and some combinations also contain acetaminophen. Read every Drug Facts label and count active ingredients across products; see our acetaminophen guide for why that matters.
Keep cough medicines out of reach of children and store them as the label directs; Robitussin DM says do not refrigerate.
When to see a doctor
Stop use and ask a doctor if a cough lasts more than 7 days, comes back, or occurs with fever, rash or a headache that lasts; the labels say these could be signs of a serious condition. Seek care quickly for trouble breathing, wheezing, chest pain or coughing up blood. For a scratchy throat, see our throat lozenges guide.
Ingredients and sodium
Each 5 mL of Delsym contains sodium 7 mg, and its inactive ingredients include high fructose corn syrup, sucrose and FD&C yellow no. 6. Each 20 mL of Robitussin DM contains sodium 20 mg, with FD&C blue no. 1 and FD&C red no. 40 among its inactive ingredients. If you watch sugar or avoid certain dyes, compare labels before buying.
What to look for when you buy
Delsym 12 Hour cough relief liquid
Best for: Long-lasting relief of a dry cough
Its label lists dextromethorphan equal to 30 mg per 5 mL, dosed every 12 hours.
Watch out: Not for children under 4; do not use with MAOIs.
See options on AmazonRobitussin Cough + Chest Congestion DM
Best for: Cough with chest congestion
Its label lists dextromethorphan HBr 20 mg and guaifenesin 200 mg per 20 mL.
Watch out: Adult product; not more than 6 doses in 24 hours.
See options on AmazonOral medicine dosing syringe and cup set
Best for: Measuring liquid doses accurately
The FDA advises using the dosing device that comes with a medicine, not household spoons.
Watch out: Use the device packaged with each specific product when provided.
See options on AmazonQuestions people ask
- What is the best cough medicine for a dry cough?
- A dextromethorphan cough suppressant such as Delsym targets the impulse to cough, per its label.
- How long does Delsym last?
- It is dosed every 12 hours; adults take 10 mL, not more than 20 mL in 24 hours.
- What does DM mean on cough medicine?
- It refers to dextromethorphan, a cough suppressant.
- Can toddlers take cough medicine?
- The FDA does not recommend OTC cough and cold medicines under 2, and Delsym says do not use under 4.
- Can I take cough medicine with antidepressants?
- Not with MAOIs or within 2 weeks of stopping one; ask a pharmacist about other medicines.
Sources
- Delsym (dextromethorphan polistirex) extended-release suspension label (dailymed.nlm.nih.gov), DailyMed, U.S. National Library of Medicine
- Robitussin Cough + Chest Congestion DM label (dailymed.nlm.nih.gov), DailyMed, U.S. National Library of Medicine
- Should You Give Kids Medicine for Coughs and Colds? (fda.gov), U.S. Food and Drug Administration