Nonalcoholic fatty liver disease (NAFLD) is a hepatic condition characterized by excessive fat accumulation, leading to liver fibrosis, cirrhosis, and cancer. Currently, invasive liver biopsy is the only method for identifying and classifying NASH. Mass spectrometry-based proteomics can detect crucial proteins and pathways involved in NASH development. A study using liver and serum samples from mice and humans found altered proteins involved in detoxification, fibrosis, inflammation, and fatty acid metabolism. These findings provide insights into NASH molecular mechanisms and potential diagnostic biomarkers for early diagnosis.