Background: Mosquito coils are widely used to control mosquitoes due to their low cost. However, their combustion releases harmful pollutants. Objective: This study investigates the histological changes in rat liver due to exposure to mosquito coil smoke containing d-trans allethrin. Methods: Eighteen Wistar rats were divided into three groups: control (Group A), exposed for 4 weeks (Group B), and exposed for 6 weeks (Group C). The rats were exposed to the smoke for 8 hours daily. Liver tissues were collected, fixed, sectioned, and stained for histological analysis. Results: Prolonged exposure to mosquito coil smoke leads to significant liver damage and inflammation due to the release of fine particles and toxic compounds. Conclusion: Long-term exposure to mosquito coil smoke is hepatotoxic. Public awareness and measures to minimize exposure are necessary.