To evaluate the possible toxicity of the aqueous extract of Echinodorus grandiflorus in pregnant rats, animals were distributed in groups treated with 250, 500 and 1,000 mg/kg/day, by gavage, and a control group received saline solution. The treatment was carried out for 15 consecutive days, remaining during mating and until the 14(th) day of gestation. On the 15(th )day, pregnant animals were euthanized by exsanguination under anesthesia. A blood sample was destined to the hematological and biochemical analysis. The ovaries, liver, kidneys, spleen, and adrenal glands were removed and weighed. Liver, kidneys and spleen were processed for histopathological analysis. The number mated, cohabitated and pregnant rats were counted as well as the corpora lutea, implants, resorptions, and live and dead fetuses. Fetus body weight and placenta were measured. Treatment with 1,000 mg of extract caused anemia, leukocytosis, and an increase in AST and in cholesterol. The liver of animals treated with the two higher doses exhibited discrete inflammatory reaction, located mainly at the stroma which supports the portal space; in the kidneys of animals of T-500 and T-1000 groups there was an expressive decrease in the capsular space, and focal areas of vasodilatation and congestion, as well as a discrete hyalinization, and in the spleen of T-1000 group the red pulp presented excessive pigmentation suggestive of hemosiderin. There were no alterations in reproductive parameters, in fetus external morphology or in placenta weight. In conclusion, the extract causes maternal toxicity, though it does not alter the reproductive performance.