The objective of this study was to examine the effect of administering an ethanol extract obtained from basil leaves on the expression of vascular endothelial growth factor (VEGF) and the severity of endometriosis lesions in a mouse model. A total of 28 female mice, aged 2-3 months and weighing 20-30 grams, were randomly divided into four groups: the control group (C), treatment group 1 (T1) receiving a dose of basil leaf ethanol extract (0.21 mg/g-BW), treatment group 2 (T2) receiving a higher dose (0.42 mg/g BW), and treatment group 3 (T3) receiving the highest dose (0.84 mg/g-BW). Each group underwent a 14-day treatment period, and tissue samples were collected on the 29^th day. An immunohistochemical examination was conducted to assess the expression of VEGF and evaluate the severity of endometriosis lesions. The statistical analysis of VEGF expression revealed a significant difference (p=0.026; p<0.05), with the most pronounced effects observed when administering basil leaf ethanol extract at doses of 0.21 mg/g-BW and 0.42 mg/g-BW. Although not statistically significant (p=0.271; p<0.05), a reduction in the severity of endometriosis lesions was observed following the administration of basil leaf ethanol extract at doses of 0.21 mg/g-BW and 0.42 mg/g-BW. Administering basil leaf ethanol extract at doses of 0.21 mg/g-BW and 0.42 mg/g-BW effectively decreased VEGF expression and limited the severity of endometriosis lesions.