N-Acetylcysteine is useful in the short-term treatment of severe Raynaud's phenomenon and digital ulcers (DU) in patients with systemic sclerosis (SSc), but its long-term effects are largely unknown. The aim of this study was to report long-term outcome (median follow-up 3 years) in a prospective study of a cohort of 50 consecutive patients with SSc who received N-acetylcysteine (NAC) infusional therapy every 2 weeks. We observed a reduction of DU/patient/year (4.5 +/- 3.1 vs 0.81 +/- 0.79) and DU ulcer visual analog scale (VAS; 6.88 +/- 2.62 vs 3.20 +/- 1.80), a decrease of the Raynaud's phenomenon (RP) number attacks (7.18 +/- 3.87 vs 3 +/- 1.92), and RP VAS (6.24 +/- 1.92 vs 3.62 +/- 1.48). In this study, we did not observe serious adverse events in patients. Minor side effects were flushing (two patients) and headache (one patient). NAC infusion was generally well tolerated, and nobody had to discontinue the treatment. In conclusion, long-term therapy with NAC, in patients with SSc, has a durable effectiveness on ischemic ulcers and Raynaud's phenomenon.