Background: metformin is now quite concern because it has been associated with a significant decrease in plasma triglycerides, total plasma cholesterol, LDL cholesterol, VLDL cholesterol and a significant increase in plasma HDL cholesterol. Objective: to find out the effects of metformin on high-fat diet-induced hyperlipidemic rats. Materials and Methods: rats were divided into six groups (n=7). One group untreated and five group (positive, negative control, and three other groups were variation doses of metformin). Negative group was given 0,5% CMC, positive group was given simvastatin dose 1.8 mg/200 g/day orally, and three variation dose groups of metformin is 45 mg/200 g BW rats/ day orally ; 90 mg/200 g BW rats/day orally; and 180 mg/200 g BW rats/day orally. Induction was given for 28 days using a high-fat diet (standar feed: quail egg yolk: butter 50:40:10) and 0,01% PTU drinking water. For orally induction using quail egg yolk: high fructose corn syrup: butter (80:15:5) and 0,1% PTU. After that, continued for 14 days treated with an oral administration. The measurement of lipid profile was carried out by the colori enzymatic method. Samples use blood serum were taken through sinus orbital eye rats as much as 1.5 mL. Results: all dose of metformin significantly decrease total cholesterol and LDL (p < 0.05) compared with the normal control. Metformin dose 3 significantly decrease triglycerides (p < 0.05) compared with the normal control and increase of HDL only occurs in metformin dose 2 (p < 0.05) compared with the normal control. Metformin dose 2 and 3 has similar effect (p < 0.05) compared with positive control. Conclusion: Based on these results, metformin has a potential effect antihyperlipidemic but not dose dependent.

Key words: Cholesterol, High-fat diet, Triglycerides, Metformin, Off-label