Acetylcysteine has been shown to enhance the response to interferon-&agr;(IFN&agr;) in patients with hepatitis C and phase II trials are being conducted in Spain and Italy for this indication.Preclinical investigation of acetylcysteine for hepatitis B has been conducted at the Max-Planck-Institut für Biochemie in Germany; however, no further development for this indication has been reported. Acetylcysteine is marketed as Fluimucil® by Zambon and as Mucomyst® by AstraZeneca (formed by the merger of Astra and Zeneca in April 1999) for the treatment of chronic bronchitis. The drug was in phase I/II trials in the US and Spain for the treatment of HIV infection; however, no recent development has been reported.Acetylcysteine is also being investigated in a large clinical study in Italy as a treatment for systemic scleroderma; its antioxidant properties may prevent the effects of oxidative stress in these patients. In addition, preclinical investigation at the University of Occupational and Environmental Health in Japan indicates that acetylcysteine may have potential for the treatment of cadmium cytotoxicity.