AbstractThe toxic subchronic effect of an extract ofAralia mandshuricaon rats of both sexes was studied over a period of 90 days (0.2, 1.7, 3.4 g/kg p.o.). The toxic effects ofAralia mandshuricaon the following enzymes were evaluated: alanine amino transferase (ALT), aspartate amino transferase (AST), serum alkaline phosphatase (SAP), total proteins and serum urea. Blood samples were obtained by means of retroorbital puncture with a microcapillary tube on days 15, 30, 45, 75 and 90 of the administration ofAralia mandshurica.The body weight was registered every week, and at the end of the study a necropsy was performed and the liver, lungs, kidneys, heart, spleen, gonads and adrenal glands were weighed. Liver, gonads and kidneys were examined histologically.There was an increase in the levels of AST and SAP enzymes with a dose of 3.4 g/kg in both sexes on day 90 of administration, but no changes were observed in urea and serum protein. A significant decrease of the body weight was recorded in both sexes with a dose of 3.4 g/kg. Moreover, the animals treated with doses of 1.7 and 3.4 g/kg showed a diminution of faecal consistence. An increase of the liver weight was produced with all the doses ofAralia mandshurica, but neither macroscopic nor histological alterations were observed, as in the rest of the organs. Possible liver damage associated with this enzyme is discussed.