The toxic effects of chronic oral administration (60 days) of aqueous crude extract (AE) of Plantago australis Lam. (Plantaginaceae) in rats at doses of 850 and 1700 mg/kg on biochemical (ALT, AST, creatinine, urea, glucose, alkaline phosphatase, total proteins and albumin), hematological (complete hemogram), and histopathological (heart, lung, liver, kidney, esophagus, stomach and gut) parameters were studied. All biochemical and hematological parameters were found to be in the normal range, but ALT in animals that received AE of 850 mg/kg was higher. Histopathological analysis of organs, especially the liver did not present alterations.