Abstract. Utami AS, Harini M, Handajani NS, Hidayat LN. 2020. Effect of carrot leaf juice (Daucus carota) on the lung histology structure of white rats (Rattus norvegicus) induced by cigarette smoke. Cell Biol Dev 4: 40-45. Cigarette smoke is hazardous to both active and passive smokers. The impact results in oxidative stress, which results in cell damage across the lung's histological structure, including tissue dilation in the alveoli, epithelial abrasion, and other abnormalities. Carrot leaves contain beta carotene, an antioxidant that can help repair damaged cells caused by cigarette smoke's oxidative stress. The goal of this study was to assess the histological structure of the lungs following induction with cigarette smoke and the influence of carrot leaf juice (Daucus carota L.) on the lung structure following induction with cigarette smoke. A completely randomized design (CRD) with five replications was adopted in this investigation. The rats were divided into four groups: those induced by cigarette smoke and given 4 mL distilled water, those induced by cigarette smoke and given 4 mL carrot leaf juice (2 mL carrot leaf juice added to 2 mL distilled water), those induced by cigarette smoke and given 4 mL carrot leaf juice (3 mL carrot leaf juice added to 1 mL distilled water), and those induced by cigarette smoke and given 4 mL oat straw juice. For 14 days, white rats were provoked with three cigarettes every day. On the 31st day, rats were killed via cervical dislocation, their lungs were removed, and histological preparations using the paraffin method and Hematoxylin-Eosin staining were performed. Quantitative data were analyzed using non-parametric techniques Anova test, and qualitative data collection by describing the effect of cigarette smoke before and after carrot leaf juice administration.