America's Compounding Center says the following about N-Acetyl Cysteine (NAC):
"N-acetyl cysteine, also known as acetylcysteine or NAC, is an antioxidant related to the amino acid cysteine. N-acetyl cysteine is commonly used to treat acetaminophen (Tylenol) overdose; however, there are many other uses for this medication. N-acetyle cysteine is also used to relieve respiratory symptoms associated with chronic bronchitis, cystic fibrosis, and reduce mucous in other lung conditions, and to prevent liver and kidney damage. It is used in patients with mitochondrial disease dues to its antioxidant effects. Dosing depends on the indication, but oral dosing for chronic conditions generally ranges from 200-600 mg two to three times daily. Side effects of n-acetyl cysteine include nausea, vomiting, diarrhea, rash, headache and drowsiness."