Robitussin has long been a trusted brand when it comes to treating coughs at home. Robitussin products are sugar free and non drowsy, menaing thye won't affect you driving or working. Their most popular cough syrup is Robitussin Dry, which contains Dextromethorpan and treats dry and scratchy, non productive coughs. A chesty cough version is also available, which contains Guaifenesin to treat coughs with a lot of mucus or phlegm in the chest.