N-Acetylcysteine (NAC) has been proposed to be used to treat Coronavirus Disease 2019 (COVID-19). By reviewing the existing pathological studies of COVID-19, it was found that abundant mucus secretion, formation of a hyaline membrane (supportive of acute respiratory distress syndrome), and interstitial fibrous exudation may be important characteristics of COVID-19 and pathological targets of drug therapy. In addition, multiple extrapulmonary organ injuries in COVID- 19 may be associated with cytokine storm. NAC is an important antioxidant and anti-inflammatory drug. NAC has been demonstrated to have mucolytic effects in bronchitis, relieve respiratory failure in acute respiratory distress syndrome, and inhibit fibrous exudation in interstitial lung disease in clinical studies. These findings suggest that NAC may have a therapeutic effect on the pathological targets of COVID-19. Furthermore, NAC decreases TNF-α, IL-1β, IL-6, IL-8, IL-10, and IL-17 serum levels in patients with sepsis, severe burns, acute liver failure, or peritoneal dialysis and may also reduce cytokine storm in COVID-19. The antiviral effect of NAC on other respiratory viruses may also benefit COVID-19 patients. Summarizing the potential mechanisms of NAC in treating COVID-19 suggests that the role of NAC in COVID-19 treatment is worthy of further research.