Cissampelos sympodialis Eichl. (Menispermaceae) has been investigated about its botanical, chemical, pharmacological and toxicological aspects in our laboratory. Previous acute toxicology studies demonstrated that in dogs as well as in Wistar rats, 5 g/kg, p.o., and 2 g/kg, i.p. of the aqueous fraction of the ethanol extract of the leaves of Cissampelos sympodialis (AFL), induced a significant increase in the phosphatase alkaline and gama glutamil tranferase (GGT) levels, that were completely reversed in 15 days after interruption of AFL treatment. The aim of the present work was to investigate the subacute toxicology effects induced by AFL in dogs. We used the methods proposed by Portaria 116/96 of the Secretaria Nacional de Vigilância Sanitária, which regulates studies of toxicity for phytomedicines in Brazil. Daily administration (p.o.) of AFL, 45 mg/kg/day (5 times the dose used by human beings), during 4 weeks, was devoid of any effect on haematological (haemogram and platelets) and on blood biochemical parametes. In conclusion, the present study, using dogs, demonstrated that AFL, in a popularly used dose, by human beings, was devoid of any toxicological effect.