Key takeaways
Mucinex and Mucinex DM are both over-the-counter medications that are used to treat cough. They both contain guaifenesin as their active ingredient. But Mucinex DM also contains dextromethorphan. Guaifenesin thins and loosens mucus in the airways. Dextromethorphan stops coughing from happening by shutting down your cough reflexes. If you have a “wet” cough, taking Mucinex on its own may be enough. If your cough is dry, a product with dextromethorphan, like Mucinex DM, may be better.
