Current evidence suggests that N-Acetyl Cysteine (NAC) administration may help improve outcomes in people with acute respiratory distress syndrome and acute lung injury - conditions that closely resemble the signs and symptoms of COVID-19. Few mild and transient adverse events were reported in published randomised-controlled trials, indicating that NAC may be reasonably safe. These findings suggest that NAC may complement the management of COVID-19 infection, particularly when administered intravenously within an intensive care unit (ICU) environment. Verdict Current evidence suggests that N-Acetyl Cysteine (NAC) administration may help improve outcomes in people with acute respiratory distress syndrome (ARDS) and acute lung injury (ALI) - conditions that closely resemble the signs and symptoms of COVID-19. In this rapid review, NAC was predominately administered intravenously to patients with ARDS or ALI, who were at risk of or requiring mechanical ventilation, and were admitted to a hospital intensive care unit. Findings indicated that NAC administration may assist in improving markers of inflammation or oxidation, systemic oxygenation, the need for / duration of ventilation, rate of patient recovery and clinical improvement score. The effects of NAC on patient length of stay, CT/x-ray images, mortality rate and pulmonary complications were inconclusive. Few mild and transient adverse events were noted, indicating that NAC may be safe for use in acute respiratory distress syndrome or acute lung injury. Based on the evidence identified, and the similar symptomatic profiles of ARDS/ALI and COVID-19, the findings suggest that NAC may be used to complement the management of COVID-19 infection within an acute care setting. The safety and efficacy of orally administered NAC for the management of milder forms of COVID-19 infection within the community setting, remains uncertain. The current research evidence suggests NAC warrants further research for acute respiratory viral infections, including COVID-19.