Cell necrosis can induce profound inflammation and potentially increases overall tissue injury. One important example is acetaminophen-induced liver injury (AILI), in which the initial tissue injury caused by the toxicity of acetaminophen (APAP) is followed by the second wave of tissue injury caused by cell necrosis and inflammatory responses. In the present study, we show that the TLR4-dependent activation of IL-1a in kupffer cells is critical for the progression of AILI. Notably, interference of IL-1R1 or IL-1a, but not IL-1b or NLRP3 inflammasome, exhibited reduced hepatic injury, as evidenced by decreased serum levels of alanine and aspartate aminotransferases, decreased hepatic necrosis, decreased neutrophils and monocytes infiltration and improved survival of experimental animals. The secreted IL-1a was derived from kupffer cells and the maturation and activation of IL-1a was dependent on TLR4/MyD88 signaling. Moreover, the infiltrated Gr-1 positive myeloid cells serve as target cells in response to IL-1a to contribute to liver injury. Taken together, these findings indicate that inhibition of IL-1a signaling can alleviate the acute inflammatory responses and tissue injury, and represent a potential therapeutic method in AILI.