Active Ingredients (in each extended-release BI-Layer tablet) - Purpose. Dextromethorphan HBr 30 mg - Cough suppressant. Guaifenesin 600 mg - Expectorant. Inactive Ingredients: Carbomer Homopolymer Type B; D&C Yellow #10 Aluminum Lake; Hypromellose, USP; Magnesium Stearate, NF; Microcrystalline Cellulose, NF; Sodium Starch Glycolate, NF.