NAC is a great supplement. It's awesome stuff to support healthy lungs. NAC is a known mucolytic. That is a fancy term meaning breaking up mucus. Now, research does show that NAC Survival of Guinea Pig Pups in Hyperoxia Is Improved by Enhanced Nutritional Substrate Availability for Glutathione Production Pediatric Research Full article: Role of glutathione in immunity and inflammation in the lung Disturbances of the Lung Glutathione System in Adult Guinea Pigs Following Neonatal Vitamin C or Cysteine Deficiency Levels of Reduced Glutathione (GSH) in Plasma and Lungs of Control and Download Table Amazon.com: Biotics Research NAC N Acetyl L Cysteine, 500 Milligram, Glutathione Production, Detoxification Support, Muscle Recovery, Healthy Lungs. 180 Caps : Health & Household