Expectorants are drugs that loosen and clear mucus and phlegm from the respiratory tract. The expectorant described here, guaifenesin, is a common ingredient in cough medicines. Some cough medicines contain other ingredients that may cancel out guaifenesin's effects. Guaifenesin is an ingredient in many cough medicines, such as Anti-Tuss, Dristan Cold &Cough, Guaifed, GuaiCough, and some Robitussin products. Some products that contain guaifenesin are available only with a physician's prescription; others can be bought over-the-counter. They come in several forms, including capsules, tablets, and liquids. The recommended dose is 200-400 mg every 4 hours, with no more than 2,400 mg in 24 hours, for adults and children 12 and over; for children 6-11, 100-200 mg every 4 hours, with no more than 1,200 mg in 24 hours; for children 2-5, 50-100 mg every 4 hours, with no more than 600 mg in 24 hours. It is not recommended for children under 2. Do not take more than the recommended daily dosage. Guaifenesin is not meant to be used for coughs associated with asthma, emphysema, chronic bronchitis, or smoking; or for coughs that produce a lot of mucus. A lingering cough could be a sign of a serious medical condition. Coughs that last more than 7 days or are associated with fever, rash, sore throat, or lasting headache should have medical attention. Call a physician as soon as possible.

Some studies suggest that guaifenesin causes birth defects. Women who are pregnant or plan to become pregnant should check with their physicians before using products with guaifenesin. Whether guaifenesin passes into breast milk is not known. Side effects are rare, but may include vomiting, diarrhea, stomach upset, headache, skin rash, and hives. Guaifenesin is not known to interact with any foods or other drugs. However, cough medicines that contain guaifenesin may contain other ingredients that do interact with foods or drugs. Check with a physician or pharmacist for details about specific products.