D. Pérez, J. Iannacone, and H. Pinedo. 2010. Toxicological effect from the stem cortex of the amazonic plant soapberry Paullinia clavigera (Sapindaceae) upon three arthropods. Cien. Inv. Agr. 37(3):133-143. Toxicological effects of four extracts proceeding from the stem cortex of the amazonic plant Paullinia clavigera D.R. Simpson (Sapindaceae) by decoction, ethanolic, chlorophormic and hexanic on three arthropods: Rhynchophorus palmarum (Linnaeus, 1758) (Curculionidae), Eupalamides cyparissias (Fabricius, 1777) (Castniidae) and Artemia franciscana (Kellog, 1906) (Artemiidae) in Ucayali, Peru were studied. The four extracts at the highest concentration tested were: decoction at a proportion 1:10 (w/v), ethanolic, chlorophormic and hexanic at 100 mg•L-1. Toxic effects were evaluated at 12, 24, 48 and 72 hours on larvae of III instar of R. palmarum and larvae of II instar of E. cyparissias; and at 24 and 48 hours on nauplii of A. franciscana. Toxicity in terms of LC 50 on the three arthropods evaluated depends of type of extract of soapberry employed. In R. palmarum, decoction (LC 50-72H = 59.15%) presented a high toxicity, although a significant effect of hydroalcoholic extract was observed at 40 mg•L 1 in comparison with control. The extracts of decoction (LC 50-72H = 70.71 %) and ethanolic (LC 50-72H = 66.21 mg•L-1) presented high toxicities on E. cyparissias, and finally, hexanic extracts (LC 50-48H = 18.79 mg•L-1), decoction (LC 50-48H = 23.82 %) and chlorophormic (LC 50-48H = 23.64 mg•L-1) presented the highest toxicities on A. franciscana. In the phytochemical analysis, saponins showed a very positive reaction in hydroalcoholic extract, and flavonoids and phenols had a very positive reaction in extract of decoction. The triterpenes were present only in the hexane extract. The hydroalcoholic and decoction extract showed toxicity on the two pest R. palmarum and E. cyparissias, but only the hydroalcoholic compared to the other three extracts had the lowest effect of risk and higher selectivity to the aquatic environment on A. franciscana.