The hydroalcohol extract (HAE) of Calendula officinalis L. was evaluated for its acute toxicity by the oral route in rats and mice and for the subacute effect on hematological, biochemical and morphologic parameters in rats. In the acute toxicity test, HAE failed to cause death in the animals after administration of oral doses up to 5.0 g/kg. Oral treatment with HAE at 0.025, 0.25, 0.5 and 1.0 g/kg did not induce hematological alterations when compared with the control group. In the biochemical parameters, there was an increase in blood urea nitrogen (BUN) and in alanine transaminase (ALT) levels. Morphological examination of the brain, kidney and heart did not show any alteration. However, inflammatory sites were found in the lung and liver, which were associated, respectively, with oral gavage and a possible hepatotoxic effect. HAE was non-toxic in rats, although there was evidence of renal and liver overload.