The present work carried out the quantification of total polyphenols in the aqueous extract of the leaves of Aloysia gratissima, and its oral absorption index in Wistar rats. For this, 20 adult rats were divided into five treatment groups: saline solution; 100 mg/Kg of A. gratissima extract; 50 mg/Kg and 100 mg/Kg of rutin and co-treatment with 50 mg/Kg of extract and 10 mg/Kg of rutin, performed orally for 14 days. For the quantification of total polyphenols, the Folin Ciocalteau method was used. In the extract, the concentration of total polyphenols was 7.11 mg GAE/mL, in the plasma of control animals the baseline level was 4.3 mg GAE/mL. In the treated groups, significantly higher values were observed, of 9.32 mg GAE/mL, 6.65 mg GAE/mL, 8.34 mg GAE/mL and 10.14 mg GAE/mL, respectively. Such data configure A. gratissima as a good source for obtaining total polyphenols due both to its high concentration in the extract and also to their good bioavailability.