Acute lung injury (ALI) is a severe and potentially life-threatening condition characterized by a sudden onset of inflammation in the lungs, leading to impaired gas exchange and oxygenation. ALI is often caused by a variety of factors, including pneumonia, sepsis, trauma, or inhalation of harmful substances. The hallmark of ALI is the presence of diffuse alveolar damage, which leads to the accumulation of fluid and protein in the air sacs of the lungs, making breathing difficult. Patients with ALI may experience symptoms such as shortness of breath, rapid breathing, and low oxygen levels. Treatment for ALI typically involves supportive care, such as mechanical ventilation to help with breathing, as well as addressing the underlying cause of the injury. Research in this area focuses on better understanding the mechanisms that lead to ALI, developing new treatment strategies, and improving outcomes for patients with this serious condition.