Mivotilate is an orally active hepatoprotective agent for the treatment of liver cirrhosis and hepatitis-B infection. Mivotilate was shown to exert multiple effects on the hepatic cytochrome P450 system, particularly to inhibit CYP2E1 expression and to up-regulate the CYP1A1 expression. The low oral bioavailability of Mivotilate in rats could be primarily attributed to poor absorption and considerable hepatic and gastrointestinal first-pass effects. The thermal reversible microemulsion system of YH439 greatly enhances the bioavailability of YH439 after oral administration. Mivotilate prevents mutagenesis caused by agents such as benzopyrene and reduces skin tumours induced by these agents.