Is it OK to take Mucinex DM and Delsym together?
You do not want to take Delsym along with Mucinex DM as they both contain the same ingredient.
Delsym contains the cough suppressant dextromethorphan.
Mucinex DM contains two products, dextromethorphan and guaifenesin.
Taking both would result in take a double dose of the dextromethorphan.
You certainly need to be careful when taking a lot of over the counter medications and many of them contain the same or combinations of the same ingredients. Both dextromethorphan and guaifenesin are very common ingredients in cold/cold medications.