Other Information: Store between 68-77 degrees F (20-25 degrees C). Misc: 600 mg guaifenesin. Relieves chest congestion. Thins and loosens mucus. Immediate and extended release. Health. Hygiene. Home. Questions? 1-866-Mucinex (1-866-682-4639). You may also report side effects to this phone number. Unique Bi-Layer Tablet: Immediate-release layer/ Extended-release layer. Choose from the Mucinex line of products to treat your symptoms. Mucinex: relieves chest congestion; thins and loosens mucus for 12 hours. Mucinex DM: controls cough; thins and loosens mucus for 12 hours. Mucinex D: clears nasal/sinus congestion; thins and loosen mucus for 12 hours. Please visit our web site www.mucinex.com. Made in England.