Shop for Guaifenesin Products at Walmart.com. Save money. Live better. What is guaifenesin and what are its uses? Guaifenesin treats coughs associated with colds and minor upper respiratory tract infections in individuals 12 years and older. Guaifenesin is an expectorant used for wet cough. It helps loosen phlegm in the throat and chest so you can cough it up more easily. Guaifenesin is an immediate-release medication that's available as a tablet and liquid solution. It's taken by mouth, typically every 4 hours, by adults and children. Guaifenesin is commonly used to treat chest congestion caused by the common cold, flu, bronchitis, and other illnesses. Guaifenesin may also be used for other conditions as determined by your. Guaifenesin is an expectorant that loosens phlegm and thins bronchial secretions to clear airways and make coughs more productive in conditions like colds, flu, allergies, and stable chronic bronchitis. Guaifenesin is an ingredient in cough and cold medicines that is used to help clear mucus or phlegm from your chest when you have had a cold or flu. Guaifenesin works by making your mucus thinner and easier to cough up, which helps clear chest congestion. Guaifenesin's neurological properties first became known in the late 1940s. Guaifenesin is a centrally acting muscle relaxant used routinely in large-animal veterinary surgery. Guaifenesin is used to treat coughs and congestion caused by the common cold, bronchitis, and other breathing illnesses. Learn about side effects, drug interactions, dosages, warnings, and more. Guaifenesin is used to help clear mucus or phlegm (pronounced flem) from the chest when you have congestion from a cold or flu. It works by thinning the mucus or phlegm in the lungs. This medicine is available both over-the-counter (OTC) and with your doctor's prescription. Guaifenesin is in countless cold medicines, but does it actually work? Here’s what the clinical evidence really says about this common expectorant.