Saponins are glycosides widely distributed in the plant kingdom and are found in many foods. The hepatoprotective potential of glucuronogypsogenin (GG) and gypsoside (GY) towards isolated rat hepatocytes treated by three toxic models used at sub-lethal doses: galactosamine (5 x 10(-3) M), CCl4 (5 x 10(-4) M) and erythromycin (5 x 10(-4) M) was investigated. Two schedules were carried out corresponding to curative or preventive treatment. No protection was observed on hepatocytes treated with GY before or after addition of the toxicants. In contrast, a protective action was detected when hepatocytes were pretreated with GG (5 x 10(-5) M) as probe, by the normalisation of LDH leakage and ATP content. It depends on the toxicant: the cytoprotective spectrum is 5 x 10(-5) to 5 x 10(-7) M with galactosamine; 5 x 10(-5) to 5 x 10(-6) M with CCl4; and around 5 x 10(-5) M with erythromycin. Taking into account the importance of LDH as an indicator of membrane damages, GG was assumed to interact with membrane hepatocyte.