Traditional medicine is the oldest and culture-based method of the health care system. Among therntraditional medicine practices, the use of herbal medicines is the most popular and used by mostrnpopulations around the globe. M. stenopetala is one of the herbs used as a treatment for variousrnillnesses in different Ethiopian societies. Although there are some data available regarding thernvarious biological activities of the different parts of Moringa plants, that of safety study is scarce,rnespecially relating to the extract of its seeds. The objective of this study was to evaluate the acute andrnsub-chronic toxic effect of orally administered aqueous extracts of M. stenopetala seeds on gross andrnhistopathology of kidneys and liver, and some blood parameters of Wistar rats. rnFor the acute toxicity study, 15 female rats were randomly divided into five groups with three rats inrneach group. The experimental groups (Groups I - IV) received a single dose of 300mg/Kg,rn2000mg/kg, 3500mg/Kg, and 5000mg/kg of the extract, respectively, while the control group (GrouprnV) received distilled water orally. For the sub-chronic toxicity study, 24 rats for each sex werernrandomly divided into four groups, each group comprising of six rats. The rats in the experimentalrngroups (Groups I - III) received 250mg/Kg, 500mg/Kg, and 1000mg/kg oral dose of the extract forrn90 days, and the control group (Group IV) received distilled water for a similar duration. rnIn an acute toxicity study, LDrn50rn of the aqueous extract of M. stenopetala seeds was found to be abovern5000mg/Kg dose. There were no observed apparent significant differences between the experimentalrngroups and the control group in body weight gain, relative kidneys and liver weight, and grossrnpathological changes at the end of the 14 days experimental period. In the sub-chronic toxicity study,rnthere was no mortality in all experimental rats of both sexes. Besides, there were no substantialrnchanges in the general condition, hematological and biochemical values, and relative organ weight ofrnthe kidney and liver. Moreover, the light microscopic histopathological examination of sections ofrnthe kidney and liver showed no change in the treatment groups as compared with the control group inrnboth sexes. Therefore, this study demonstrated that 90 days oral administration of aqueous M.rnstenopetala seeds extracts are relatively safe in rats up to 1000mg/Kg dose.