Active Ingredient (in each Extended-Release Bi-Layer Tablet): Guaifenesin (600 mg). Inactive Ingredients: Carbomer Homopolymer Type B, FD&C Blue 1 Aluminum Lake, Hypromellose USP, Magnesium Stearate NF, Microcrystalline Cellulose NF, Sodium Starch Glycolate NF.