Nelumbo nucifera Gaertn is widespread and a popular food in central and southern Taiwan. It has also been reported to possess different therapeutic effects, but the effects of N. nucifera leaf on lipid metabolism and liver function remain unclear. In this study, a high fat diet was used to induce hyperlipidemia, hypercholesterolemia, and fatty liver in hamster. The effects of flavonoid-enriched N. nucifera leaf extract supplement and two lipid-lowing drugs, silymarin and simvastatin, on the disorders induced by high fat diet were investigated. The results showed that a 10-week application of a high fat diet to hamsters led to significant increases of body weight, plasma lipid derivatives (triglyceride, total cholesterol, and lipoproteins), lipid peroxidation, and liver damage markers (plasma aspartate aminotransferase and alanine aminotransferase). Interestingly, flavonoid-enriched N. nucifera leaf extract supplement effectively ameliorated the high fat diet-induced lipid metabolic disorders as significantly as silymarin and simvastatin did. Moreover, the flavonoid-enriched supplement alleviated the high fat diet-induced accumulation of lipids in liver, the findings showing distinguishing mechanisms from the effects of silymarin and simvastatin. These results suggested that the flavonoid-enriched N. nucifera leaf extract supplement may significantly improve the high fat diet-induced abnormal blood lipids and liver damage as significantly as the common drugs. Consequently, it is suggested that the flavonoid-enriched N. nucifera leaf extract supplement is beneficial for the improvement of lipid metabolisms and the alleviation of liver damage in high fat diet treatment.