Peumus boldus Molina (Monimiaceae), commonly referred to as ‘boldo’, is used in traditional Chilean medicine to treat hepatic and gastrointestinal diseases. Its leaves are rich in antioxidant compounds, principally alkaloids and flavonoids. This study evaluates the protective effect of a complete boldo leaf infusion on lipoperoxidation (MDA determination at 532 nm) induced by cisplatin in mice liver. To determine if the observed effect can be explained by the action of boldine or catechin, each compound was studied separately. The mice were divided into 8 groups (n = 6): (I) not treated; (II) treated with cisplatin 6 mg/Kg b.w.; (III) treated with boldo leaf infusion 5%; (IV) pretreated with boldo leaf infusion 5% and treated with cisplatin 6 mg/Kg b.w.; (V) treated with boldine 50 mg/Kg b.w.; (VI) pretreated with boldine 50 mg/Kg b.w. and treated with cisplatin 6 mg/kg.b.w.; (VII) treated with catechin; and (VIII) pretreated with catechin 50 mg/Kg b.w. and treated with cisplatin 6 mg/Kg b.w. As expected, the treatment with cisplatin significantly increased (p < 0.01) lipoperoxidation in comparison with the non-treated group. Pretreatment with boldo leaf infusion significantly diminished (p < 0.05) the lipoperoxidation induced by cisplatin with respect to the animals not pretreated with the infusion. The pretreatments with boldine and catechin significantly diminished (p < 0.05) the lipoperoxidation induced by cisplatin with respect to the group treated only with cisplatin. The results suggest that the boldo infusion is acting as a protector with respect to the oxidative hepatic damage caused by cisplatin, and that this protective ability would be due to the presence in the infusion of the natural antioxidants boldine and principally catechin. These findings suggest the potential use of the infusion as a chemoprotector. Copyright © 2009 John Wiley & Sons, Ltd.