Acute lung injury is a clinical symptom that can cause morbidity, acute respiratory failure, and risk of developing pneumonia. Mast cells are found more commonly in places where antigens can enter the body, such as skin and respiratory and digestive systems, which enables them to be among the first groups of cell to act in the defense mechanism against foreign matter entry. Resveratrol is an active substance which is found in the structure of many plants and which can be used against pathogens due to its antimicrobial effect. The aim of our study is to show the degranulation and heterogeneity of mast cells and the presence of tryptase and chymase secreted from their granules immunohistochemically in acute lung injury which occurs after blunt trauma and to research what kind of an effect resveratrol has on mast cells in this process. Twenty adult female Sprague-Dawley rats were used in the study. The rats were randomly assigned to four groups. The first group was the control group, the second was the contusion group, the third was resveratrol group, and the fourth was the treatment group in which contusion was induced following 30 mg/kg intraperitoneal resveratrol administration. In the present study, acute lung injury was created with trauma and the effects of resveratrol in this process on the distribution, heterogeneity, degranulation, and immunohistochemical characteristics of mast cells were examined. It was concluded that resveratrol, which caused a significant decrease in mast cell degranulation and increase in number following trauma, had an influential role in this process.