Osthole is a natural coumarin derivative primarily isolated from the plant Cnidium monnieri (Shechuangzi) and has been traditionally used in East Asian herbal medicine. In the context of fatty liver disease (hepatic steatosis or NAFLD), there is some preclinical scientific evidence supporting its beneficial effects. Several animal studies have reported that osthole administration can attenuate hepatic steatosis, reduce liver inflammation, and improve lipid metabolism. Mechanistically, osthole appears to exert these effects by modulating signaling pathways involved in lipid accumulation, such as AMP-activated protein kinase (AMPK), and by reducing oxidative stress and inflammatory cytokine expression in liver tissues.

For example, a 2017 study in mice found that osthole supplementation improved liver histology and decreased markers of liver injury in a high-fat diet-induced fatty liver model (Phytomedicine, 2017). Another study suggested that osthole could protect against liver steatosis by regulating lipid metabolism and inflammation through the AMPK pathway. However, it is important to note that most of the evidence comes from animal models or in vitro experiments, and there is a lack of robust human clinical trials confirming these benefits. Thus, while there is a scientific rationale and some preclinical evidence, the overall strength of evidence is limited, and more research—especially in humans—is needed to validate its efficacy and safety for fatty liver disease.