Acetylcysteine is a medication primarily used to treat acetaminophen overdose and to help loosen mucus in individuals with respiratory conditions. It works by replenishing levels of glutathione, an important antioxidant in the body, which helps to detoxify harmful substances. Additionally, acetylcysteine is sometimes used as a dietary supplement for its potential antioxidant properties. It can be administered orally or through inhalation, depending on the condition being treated. Its safety profile is generally favorable, but side effects may include gastrointestinal discomfort and allergic reactions in some individuals.