Learn about N-acetylcysteine (NAC), its uses, and potential risks. Understand how NAC may benefit your health and what precautions to consider before using it. ... Itching or rash; ...

Dr. Mike prescribes about 1,200 milligrams a day of N-acetyl cysteine, or NAC, to many of his patients with chronic obstructive pulmonary disease, a lung condition that steals your breath.

ANSWER: N-acetyl cysteine, a precursor to the amino acid cysteine, has several roles in medicine, as you say. When inhaled, it breaks up mucous, which helps people cough out thick sputum.