BACKGROUND: Obesity can lead to many diseases such as diabetes, hypertension, cancer and cardiovascular diseases, which seriously affect people's quality of life and health. AIMS OF THE STUDY: To investigate the main components and potential of n-butanol extract from Citrus aurantium L. var. amara Engl to reduce lipid accumulation and to explore its modulatory effects on the gut microbiota. METHODS: The main components of n-butanol extract were analyzed using liquid chromatography quadrupole trap mass spectrometry (LC-QTRAP-MS) and a high-fat diet-induced obese mouse model was established to analyze its effects on the determination of gene expression levels and intestinal microbiota using reverse transcription quantitative polymerase chain reaction (RT-qPCR) and 16S rRNA gene sequence method. RESULTS: The n-butanol extract mainly consists of 15 components, and it could significantly inhibit weight gain, reduce liver coefficient and improve oxidative damage. By regulating the expression of related genes, it inhibited hepatic steatosis and hypertrophy of epididymal tissue. The n-butanol extract increased the diversity of intestinal microbiota, improved the composition and structure of the flora, and reversed the high-fat diet-induced disturbance of intestinal microbiota in mice. CONCLUSION: These results indicated that the n-butanol extract of C. aurantium could inhibit lipid accumulation and provide a more comprehensive basis for the development and utilization of C. aurantium in anti-obesity activity. © 2025 Society of Chemical Industry.