Introducing Mucinex 12 Hour Cold & Fever Multi-Symptom Bi-Layer Tablets: The first and only over-the-counter cold and flu medicine that provides 12 hours of powerful multi-symptom relief from fever, headache, body pain, cough, and chest congestion. Thanks to our unique bi-layer tablet technology with an immediate-release layer and an extended-release layer, one dose lasts 3x longer than most cold and flu medicines. Starts to release medicine immediately, while the extended-release layer keeps working for 12 hours. Our one-of-a-kind formula contains powerful active ingredients that provide all day control of your worst cold and flu symptoms: Naproxen Sodium reduces fever and helps relieve headache and minor pains. Dextromethorphan HBr is a cough suppressant that helps control cough. Guaifenesin is an expectorant that thins & loosens mucus and relieves chest congestion. Say goodbye to re-dosing every 4 hours: just 1 dose (2 tablets) in the morning and 1 dose (2 tablets) at night keeps you covered for a full 24 hours. compared to 1 dose of 4-hour medicine without re-dosing.