Acute liver failure (ALF) is a rare but highly mortal condition without liver transplantation (LT). N-acetylcysteine (NAC), a glutathione precursor that detoxifies the reactive metabolite of acetaminophen and replenishes hepatic glutathione stores, is a highly effective drug for the prevention of ALF caused by acetaminophen. However, therapeutic use of NAC in non-acetaminophen-induced ALF (NAI-ALF) including alcohol intoxication, hepatitis virus infection, or drug and toxin-related hepatotoxicity is still inconclusive. The aim of this article is using meta-analysis method to analyze recent prospective clinical trials for the safety and efficacy of NAC in patients with ALF not caused by acetaminophen poisoning.