This invention relates to novel acetylcysteine compositions in solution, comprising acetylcysteine and which are substantially free of metal chelating agents, such as EDTA. Further, this invention relates to methods of making and using the acetylcysteine compositions. The present compositions and methods are designed to improve patient tolerance and compliance, while at the same time maintaining the stability of the pharmaceutical formulation. The compositions and methods of this invention are useful in the treatment of acetaminophen overdose, acute liver failure, various cancers, methacrylonitrile poisoning, reperfusion injury during cardio bypass surgery, and radiocontrast-induced nephropathy, and can also be used as a mucolytic agent.