Acetyl-L-Cysteine:
Studies for the health benefits of this amino acid cysteine derivity,  results in the recognition of the fact that it is a powerful antioxidant. When this is taken regularly, it produces, in the body, an antioxidant know as, enzyme glutathione. 

This is important to us, for it's ability to minimize mucus created from chronic smoking.  The lungs create this mucus in defense as a  protecting barrier from the smoke and its irritants. If the person has smoked for years, the mucus produced from smoking, was once a protector for the irritated lungs, then becomes the enemy to the lungs, filling up the air sacs and losing it's ability to then expell the mucus for (oxygen ) replacement.  Literally drowning from the body's own fluids.  That's what Emphysema basically is.

Bronchitis can develope from smoking or continuous bouts with pneumonia.

Regular use of this amino acid, may reduce the number of times these occurances happen.  Exactly what happens, when this amino acid is taken, is still a mystery.  Claims have been that it thins the mucus but that has not been verified.

Fluid retention has contributed to symptoms like angina, shortness of breath, then in turn, affects the heart because of no transferring of oxygen, affecting the heart in a negative way.

There is evidence that regular use of Acetyl-L-Cysteine, can help repair damage done to kidneys from the contrast dye used for diagnostics studies.