This study was designed to evaluate the acute and sub acute toxicity of the aqueous leaf extract of Sarcocephalus latifolius. The albino rats were orally administered with doses ranging from 500 to 2000 mg/kg body weight and observed continuously for the first 0h, then hourly for the next 12h and finally for 24h. Control animals received normal saline. The clinical signs of toxicity manifested in rubbing of nose and mouth on the floor of the cage, weaknesses and dizziness, loss of appetite and restlessness. To determine the toxicity characteristics of the medicinal plants such parameters as the lethal dose (LD50) as well as effects on the functions of vital body organs such as the liver and kidney were evaluated in the albino rats. For subacute toxicity, 4 groups of 4 rats of both sex each received normal saline (control), 250, 450, and 583 mg/kg of the extract respectively, once daily for 28 days. There was significant increase (p<0.05) in serum enzymes such as alanine transaminase, aspartate transaminase and alkaline phosphatase level against the control group. However, histological examination of tissue sections of liver and kidney revealed histopathological evidence of pathological lesions. The results of this study showed the toxicity characteristics of the aqueous leaf extract of S. latifolius for long time treatment at the doses used.